If you leave it blank it will use an example file: Chopin - Prelude in B flat minor Then space to play the file. Cool right! It was such a pain to make but was definitely worth it, maybe I should make an exporter, hmm... To import a midi file, go to: https://hexed.it/ Open the midi file then select all and use cmd-c to copy it, it should ask which format, select plain data, which should look like 4D32C5B5AF4... then just copy and paste it into the project and it should (hopefuly) convert it to a nice and easy to understand format. The ScratchMusic file is the same format used for my music editor: https://scratch.mit.edu/projects/1273100579 You an use this for anything, but please credit me, I spent a long time making it :) If you just want the importer: https://scratch.mit.edu/projects/1351868850