It's taken quite some time, but I've finally managed to sit down and fix the files. You should be able to grab the following package which contains all the assets, but only Day 3, which you can use as a model for your scene and modify as you wish.

I an looking forward to any good AND bad ideas you might develop with what we've given you!

The first stop if you want to mess with things should be Ren'Py's Quickstart documentation, which has numerous examples and is all-around very useful as a primer. Everything written below is stuff I've gathered after much fiddling around with the code, and while it is interesting if you're eager to get ready, it will not replace a solid look at existing documentation. :D

Click here to download a file we created that includes some tips and code you can copy/paste. I'll post some screenshots below, but for the convenience of keeping formatting, the file should be much easier to use! All of these are things you can modify easily to tell the story you want.

1 CHARACTERS
Characters have a default appearance (shown in script.rpy as "default" in # CHARACTER DOLL Headers). The rest of the attributes shown are listed under the same DOLLS headers, ordered by group (eyebrows, eyes, arms/pose, outfit for those that have one). Only one attribute per group can be displayed at a time (can't show angry AND happy eyebrows!).
When called (for instance with v22 "Hello", they'll show up in the default place (center) with their default appearance.
Showing, moving and hiding characters is done this way several ways

Note that you can already make a character appear with a different expression than the one they have by default.
After MOVING a character, always double the line to restate where the character ends up, otherwise it can cause display issues.

Example:
show red happy closedsmile at right with easeinright
show red at right

Poses and faces can be changed in separate lines or during dialog lines. Stuff that goes between the character call and the dialog is the expression change.

This new expression will stay displayed until changed, or the personnage disappears (which resets to default).
You can set an expression for this line only by putting an @ in front of it. You can add several attributes after the @ to make several of them appear only on that line.

2 SCENE TRANSITIONS

STATIC BACKGROUNDS

Static background transitions are very easy to do. There are only two types used in Love Thyself, dissolve and fade. Dissolve is very classic in that it simply transitions the new background on top of the old one. Like its name indicates, fade has a fade to black between the old background and the new one, which can indicate, for instance, the passage of time (this effect is used several times with successive hallways to mark a long time spent walking around the station).

Examples:

show bg-concourse1 with fade

show bg-greenhouse2 with dissolve

ANIMATED BACKGROUNDS

These are a little trickier to handle, because animated backgrounds are movies and not considered by the game as a normal backgrounds. It is important to remove them before changing backgrounds, and the way to do that is to simply add a "stop movie" command before the transition.

3 CHOICES

4 SOUND

Music and ambient sounds (which are stored in their respective folders in the sound folder) are short ogg sounds that are automatically set to loop. Sound effects ("sounds") are not set to loop. You can set a fade in command to make the volume progressively get louder, and a fade out for when you want the music to progressively stop. The number is seconds, and can be either a full second or 1.3, 0.5, etc.

Here is how they will usually be used.

play music "ConcourseAmbiance.ogg" fadein 1
stop music fadeout 3

play sound "BattleBridge_GunFight.ogg"

play ambient "Hallway.ogg" fadein 2
stop ambient fadeout 5

5 DEBUGGING

If you made a typo in trying to display something, or are trying to display an image that doesn't exist, the game will work, but a message will appear in red when the missing image should be displayed. You can compare names to fix your script.

Sometimes movie issues are the result of missing files being called. Check for missing files and for missing "stop movie" statements.

Indentation is critical to Ren'Py, make sure yours is correct or the project will not launch. Make sure all the options for your choices (the "menus") all have a semi-colon at the end of the option (see the sample).

If you have a question, feel free to ask it below, and we'll do our best to help you!

Download Love Thyself from Steam. 

2 Get Ren'Py

Download Ren'Py from the official Ren'Py website.

3 Create a new Ren'Py project

Boot Ren'Py and click on "+Create New Project". Select the folder in which you want Ren'Py to store your project. Name it whatever you like, it will not be the display name of the project. Pick 1280*720 as display resolution, then just click "continue" on the accent and background colors window because you're about to overwrite them anyway, and it'll create your first working files for the Ren'Py project! Whee!

Note: If it's the first time you have ever used Ren'Py, it will probably ask you to set up an editor for the rpy files. Go with your preference, I've personally used NotePad++ which you can configure to use with Ren'Py, but any will do.

4 Copy files over

Copy the files from your Steam folder over to your Renpy project folder. By default, the path is something like C:\Steam\steamapps\common\LoveThyself , so just head over to \common, click on LoveThyself, and ctrl+A / ctrl+C that stuff. Then click on Open Directory> base in Ren'Py, which will open the folder that was created for your project. Ctrl+V in there to copy the contents of the game, and boom, if you click "Launch Project"  it should now basically boot Love Thyself! Just check that it works.

5 Remove extra stuff

At this stage, you're almost ready to mess with what's under the hood already. In the Ren'Py Launcher, click on Open Directory>game and remove all the RPY files, except for script.rpy, options.rpy, gui.rpy, screens.rpy and part2-exrusfinale.rpy. Everything else goes.

6 Download the sample scene

Click here to download a simple scene, upon which you'll be able to build. Place it in your game folder. Click on Launch Project to check if everything's still peachy.

7 Start messing around!

We strongly recommend checking out the Tutorial game to get a better idea of how Ren'Py scripting works, but it isn't strictly necessary. You have a simple structure in the sample file which you can modify and expand on, and of course, you have the script of Love Thyself that you can draw inspiration from! Change backgrounds, introduce new ones, add music or sound effects, include more characters... Space's the limit!

Share your creations below (you can drag and drop the .rpy files directly), or let us know what scenes you'd like to see!

Here's a bit more documentation. First off, the Ren'Py documentation on localization can be accessed here. I don't think there's much you need to know from there before you can start translating. A very interesting guide, which I recommend you take a look at, can be found here.

To create the localization files necessary for your language, you'll have to download Ren'Py (it's free). Boot up the software, take a look at the Tutorial just because it's very informative if you want to dig into the script, and then click on +Create New Project (1). 

If it's the first time you have ever used Ren'Py, it will probably ask you to set up an editor for the rpy files. Go with your preference, I've personally used NotePad++ which you can configure to use with Ren'Py, but any will do.

The name itself doesn't matter as it's not the display name of the project. As you can see, ours is called "Horatio V2", because there was another "Horatio" project before, the very first prototype of Love Thyself! Moving on, pick 1280*720 as display, then just click "continue" on the accent and background colors window because you're about to overwrite them anyway, and it'll create your first working files for the Ren'Py project! Whee!

Then open your files browser, go to your Steam folder, and copy the contents of your Love Thyself folder. By default, the path is something like C:\Steam\steamapps\common\LoveThyself , so just head over to \common, click on LoveThyself, and ctrl+A / ctrl+C that stuff.

Then click on Open Directory> base in Ren'Py, which will open the folder that was created for your project. Ctrl+V in there to copy the contents of the game, and boom, if you click "Launch Project"  it should now basically boot Love Thyself! Just check that it works.

Now, click on "Generate Translations," which will create the required files for the localization of your choice. In "language," type whatever language you're translating into (type the English name for it to keep it easier for everyone, and make sure it's lower case). Then click on "Generate Translations" below it.

Let the thing process, and notice that your game folder now has a new subfolder, "tl", which should contain a subfolder in itself with a bunch of rpy and rpyc files.

Those are the ones you'll be working on. They only include the displayed text strings (and choices, and menus) so as not to mess up with the rest of the script.

They look like this (note that particular look may vary depending on software used. This is, once again, NotePad++ because I'm a simple man):

If you want to get started from that point on, it's easy: just start filling in the "" !

To check the results, you'll have to refer to the guide I mentioned above, which I'll just re-link because I do what I want.

Let us know if you have any questions and we'll help as best we can!