How can I create a zombie system similar to Guts and Black Powder?

I am working on making a zombie campaign game, In order to make it a quality game, I need a quality zombie system. The best zombie system i’ve seen on ROBLOX is Guts and Blackpowder zombies, I want to recreate this system. Does anyone have an idea on how I can do this?

Reminder I am not asking for scripts, I am asking for resources or potiental ways to do this.