Fan Translation requires several tools.
1. A Hex Editor. Those can be found on most any large download site.
2. A Table of english and forigen (in this case Japanese) text. For many games this is shift-JIS, but it may not be. This can be quite a pain if you have to manually figure this out yourself.
3. A script dumping and insertion programs. While not essential for smaller games, like fighting ones, a lack of one for any game with text, especially multi-paths, but really any amount of text really makes translation nth times more difficult.
4, A translator. Yes, surprise surprise, someone should speak both languages!
This is just the basics, It often gets more difficult if you want to add or remove text (because of space issues usually so you don’t get stupid lines like ‘Jack run down hill’"
Then sometimes text (sometimes quite important text) can be inserted into images and really does need to be transalted. This means you usually haveto extract the image as its not in a format you can usually easily read with your average image viewing program, then edit it and reinsert it without screwing things up.
Then of course you haveto do testing for bugs…