Up till now, I can't find any tutorial on how to use PAB on the Internet. I really want to try it out to develop Cardano Dapp. Anybody find good ones?
Lecture #6 and #10 from Plutus Pioneer Program would be a good start although it might be a bit outdated because there has been many changes since the lectures were published, and PAB itself does not have an official stable release yet.
You can also check out PAB components in the repo's README.