Ok, cool! There's pretty much zero coding involved, it's mainly just using existing things to modify files. Since they're all Nintendo or Sega specific formats, it's tough, but for most of them there are already programs to assist with modification. Most of it is designing new sprites/editing charts, not a lot else to do.
The editor isn't the easiest thing to use, but it works (takes some trial and error sometimes). It requires math to use, just basic addition/subtraction to figure out the placement of notes, but that's about it. Not super intuitive but it's there