NOOB question, how do you switch facial features in essentials

Hello, I am coming from Anime studios which has a function called a switch layer. This is basically a layer that holds different drawings that you can press a button to change, which is great for different eyes, mouth phonemes, hand gestures etc.
I am still in the early stages of my learning of TB essentials. I wonder if anyone could tell me what are a few different methods you may use to solve this problem in essentials and if there are good tutorials that would be handy too. Is there an easy way and a complicated way? If there’s an easy way that may be more my speed at the moment. Being new to this program feels like learning every part of an endless forest one leaf at a time.
I’ve been looking through this forum but don’t even know what terminology to search for. If this is a redundant thread maybe someone could refer me to the right place? Thanks so much.

In Harmony it is call Drawing Substitutions.

A good place to start, the Learn Toon Boom Website:
Harmony Essentials Kick-Start (LINK)
Educational Curriculum - Harmony Essentials (LINK)


Most appreciated, thank you so much.

Here is an official tutorial introducing the concept of drawing substitution: Drawing Substitutions - YouTube