How do I... use this? There's no help button or anything
Click "Start" admire the CP/M startup, you have an "A>" prompt go for it.
Start with
https://archive.org/details/cpm-primer-second-edition/mode/1...
Or this if you dare:
https://archive.org/details/TheCpmProgrammersHandbook/mode/1...
That was the very same reaction of many early S-100 computer owners. This emulator has done a good job emulating that.