Alright, let's get you started, this is just the basic for text:
You will need GARBRO:
https://github.com/morkt/GARbro/releases/tag/v1.5.44
Download either the setup or the portable version. Run it
Locate the game folder, and with the patch applied, you have extract 2 files into 2 folders, patch2.xp3 and data.xp3. I suggest:
game folder/data/
game folder/patch2/
Just for text (scenario files), pay attention:
in data folder, where you have extracted, copy all files out of scenario folder
copy it to somewhere, like /working/
also copy all files from /replay/ folder to /working/
Now your /working/ will have all files you need to translate, but you need the patched files
Now go to /patch2/ (that you extracted from patch2.xp3)
Copy all files inside /patch2/ into /working/
Now, your working directory have all updated files from patch2.
Start translating, I suggest you test it first with A01.ks, open it with notepad, try a few lines:
Open Garbro, this time select all files from /working/ directory, please don't select the folder, but the files:
Select create archive, name it, patch2.xp3, save it somewhere.
Now delete patch2.xp3 and patch2.sig in the game folder, replace it with your patch2.xp3
Try the game, you will the translated line:
Congratulations, but you're not done yet:
You need to also translate the interface, the options, etc, this requires knowing some photo editting skills such as gimp or photoshop.
I haven't played the game (I don't play otome game anyway lol) to know which graphics (event cg for example) that need translation but pretty much safe to say, the option graphics need to be translated.
You do it exactly like how you make patch for text: locate those graphic files in data, copy it into your working directory, translate them, and then pack them bundle all together into patch2.xp3
Do not put the files into any directory, just keep the file name the same as the original, the game engine will automatically use the new files in patch2.xp3.
And please pay attention to the updated file in patch2 folder that you extract, always use the files from patch2 folder first because that's from the 1.02 updated.