The user guide should be your first stop for understanding the high level concepts that bttf deals with. Otherwise, consult bttf --help or bttf <sub-command> --help for more specific details.
The default version is gc-eu-mq-dbg, i.e. the GameCube Europe/PAL Master Quest Debug ROM. Note: This repository does not include any of the assets necessary to build the ROM. A prior copy of the game ...