How to Best Help on the PBE?

So I'm getting back into League now after having to drop it for some time while finishing up college. Now that I've graduated, I actually have MORE time on my hands, so I can play again. I also have access to the PBE. I've never really used it much, but now that I'm getting into the game again, I'd like to help out you guys at Riot as much as I can.

So what is the best way for me to help on the PBE? Do I just play normally and post bugs here? It was never super clear to me what the intent was when I was given access.