You can download sm_osx here.
Note: while sm_osx should install homebrew for you, you will need to enter your password once if your on intel, and twice if your on arm.
sm_osx is a launcher and compiler for the Super Mario 64 Pc Port.
Yes, sm_osx is, and always will be, completly free.
Go to the Getting Started section of this page.
Just restart the app, and the terminal window should reopen
There is a auto updater in sm_osx, so if an update comes out, you will be alerted.
There are many tutorials on how to get a super mario 64 rom, I would search "Dump rom n64" and find a legal way to dump any nintendo 64 rom.
Make sure the format is .z64, if it's .n64, you can use the byteswapper here.
If it's still failing, try renaming the file to something simple, if its still broken, please make a issue.
Make sure you have Homebrew installed, if it is, please make an issue and send the log created.
The repos are stored in a folder called SM64Repos in your home folder.
Please make an issue and send the log created so I can see about fixing it.
Please create an issue in the Issues page.
Make sure you accepted them. You can check in the Notifications section in the System Settings app, or System Preferences app, find sm_osx, and turn notifications on.