In Zbrush, there are subtools that make up parts of your sculpt. These can work similarly to layers in photoshop.
In Zbrush there are many different hotkeys that will help you navigate the programme efficiently. By creating subtools it will break down your sculpt and enable you to work on different parts without affecting others. Polygroups can be used to break up areas of a sculpt on a subtool. They enable more control of your sculpt and can also help with performance on bigger sculpts.
Check out some of the other great tutorials on CGHero.