To make the songs for HMBS I took the following steps.
- Find a midi version of the Hatsune Miku song I was looking to include, you can find these in a few different places online but I mostly used onlinesequencer.
- Imported the midi file into a program like hUGETracker to see the actual notes in piano roll format. I forget what exact settings I used, but I know I had to limit the total number of channels which rendered some midi files unusable.
- I would listen to the midi file and try to isolate sections of the melody that would be recognizable and would then copy and paste those into GBStudio's Piano Roll. This took a ton of trial and error with how limited the GB Audio channels are.
- I then tuned the settings of the various instruments section-by-section for each song to get the exact sound I was looking for.
it was overall a little janky and a lot of work, but I was happy with the result.