im currently reading a computer music making guide for mac and it always refers to shortcuts that use the 'command' (command+1 for exmaple) key. where is the command key?

The "command" key on a mac keyboard is the one with the apple logo on it, there is often a "clover" on it as well, or in lieu of the apple if it is a 3rd party keyboard. Located on either side of the spacebar.