The Cold Boot Cycle
When switched on the Altair computer does not have any software loaded for operation and must be "Cold Booted" by either a program stored in ROM (like your PC) or by having a program entered using the Altair's Front Panel.
The Cold Boot cycle in summary
Ensure that your “Serial Bus” is connected and that APE is up and running on your PC.
Enter and run the Serial Boot Loader program.
Start the boot process from the APE program on the PC.
Use CP/M on your Altair with APE running on your PC.