Hello. This is my first guide. The tools needed will be:
DSDecmp or BatchLZ77
Some sense on command prompt if using DSDecmp
DSBuff or another rom packer
Section 1: unpacking and reading models
1. Open up CrystalTile2 and open up your KH 358 days rom. Go to NDS filesystem (Ctrl + N) and find some file you want that ends in .z.
2a. Extract it and run BatchLZ77. Open the file you extracted or drag into the program. Wherever you put the .z file should be a copy of the same file with .decompressed at the end.
2b. If using DSDecmp, open it in cmd, yaddah yaddah, so now it should be: DSDecmp "file" "output file". You now have a file.
3. Inside the .decompressed file are some animations and models (if a model file). Open them up in CrystalTile2 and look through. If it's actually readable then it probably isn't a model... (letters saying ABC DEFG don't count.)
4. For models: extract the BMD0s from the KAPHs is find the word BMD0 and copy every line down from that and paste that into a new BMD0 hex file. Open it up with your favorite BMD0 viewer (I have no idea how) and enjoy. Kingdom Hearts uses custom op codes so you may have to find another BMD0 reader that supports it.
Section 2: font hack for noobs
Now, this is VERY easy, all you need is crystaltile2!
1. locate sffont_10.nftr or sffont_8.nftr. select and press space. you should now have a box of letters and stuff. Double click on one and scribble, or make an awesome font and impress everyone.
Up next, text and graphics hacking. I still haven't figured out for four hours.