Turned Based Combat (Need help)

HELLO!

I am making a MiiTopia type mod and to do that I need to add a main feature

TAKING TURNS AKA TURN BASED COMBAT

But the problem is, I have NO idea where to even begin (and I definitely can't code it cause when i see code my brain has a seizure)

So i have turned to the forums in hope somebody will help me with this issue

Please and thank you.