It's not that hard. You follow the instructions to download the git, then you open the file (ex. a\0\0\2 for the main text) in PPTXT. Then, you go File -> Import All from Files and select the folder you downloaded the git to.
I was thinking about making a fix for PokeShifter on Pokemon Black. I'll need to know what info I need to change, which file it's in, what offset it's at, and what I need to change it to. I was thinking it might work like the Pal Park fix for HGSS.