BMX bike sizes? I'm a noob.?

I am 5'11", about 150 pounds. I would be riding a bmx bike, brakeless would be fine, and maybe doing grinds if I get into it. I'm dont' know what the average sizes are, but I'm sure that some size frames, weights, and tires work better with certain spots, just like with skateboarding which I've been doing for 3 years. I would be riding small gaps and stairs (no more than 5 stair height), manny pads, banks, and maybe ledges/rails. If you could tell me some basic sizes to look for when I'm at the shop would be helpful. Maybe even throwing in some good examples that I could look at online would be cool. T H A N K S !