So there was this guy who went swimming one day and got his left side bitten off by a shark.
But don't worry, he is all right now.
Alright listen up, smarty pants. This "all right now" is a play on words. Get it? The dude lost his left side, so he only has the "right" side left. It's punny because "all right" means okay, but here it means he's just got his right side. I bet you're the kinda guy who still uses training wheels, huh?