Mac keyboard shortcuts use the Apple key in conjuction with other keys to invoke an action.  For example when the Apple key and the P key are pressed at the same time, it tells OS X to perform a Print.  Just try it.  Open a document, a web page, and an email.  Press command-P in each application to see that print is always invoked with that combination.

The following images will help you to find the key with ease.

 

 

 

More recently however, Apple has made changes to the key in that the keyboards on new Mac models no longer contain the Apple icon.  In fact, some simply have the letters 'Cmd'  or 'command' written on the key in conjunction withthe ⌘ icon.   This largely depends on the Mac model and release date of the Mac.