Create a spawn class using ofxspritesheetrenderer?

Lately I’ve been using ofxSpriteSheetRenderer which I love. I’m able to create multiple instances of my sprites directly in testapp.h/testapp…cpp, but I was wondering if there was a way to simply create an enemy class (i.e. zombies) and randomly spawn instances of that class within a games screen. How would I call an instance of an enemy using a this enemy class within testapp? How would I set up the enemy class with ofxSpriteSheetRenderer, so it can be properly called within the testapp(or game screen) I’ve been trying to wrap my head as to how to do this, but I’m very new to openFrameworks. If someone can point me in the right direction even if I have to read up somewhere else - any help would be worth its weight in gold :-[