Well, technically it's my first big translation project that i have ever done.
It's kinda hard to explain how the whole process goes but it's pretty easy. You go to any scenario of any of the games (except the PC-98 ones), click on which part of the game you want to translate, write on the site the translation to each line of text and then run the community patch which fetches the changes you did on the site and patches them in the game you are trying to translate. Same thing goes with images. You translate the text of the image, edit the translation on the image and then upload it for it to be patched in the game using the community patcher.