Potty training: how and when to take the next step?

My two years old is so good with potty training. He pees on the potty every single time and has been doing so for a while. He does not poop on the potty though. He's always naked at home so he can just go to the potty whenever he needs to without having to mess with pants and underwear. But where do we go from here? Putting underwear on and teach him to take them off? I'm really scared that will set us back because he can't take his clothes off by himself yet and I'm thinking he might confuse underwear with a diaper. Do we continue this for a little bit longer as it is, or do we take the next step, and what is that next step? Need advice!