Go to any decent looking bait and tackle shop in those areas and buy a crab trap or two. Then ask the owner
(not the kid behind the counter) where you can crab and what kind of bait to use. That should get you started. I always heard that Marco Island crabs around Ft Meyers were the best on the west coast of Florida. Also, if you see someone crabbing, stop and watch what they are doing, ask some questions, then go to a similar location and do the same thing. Then read everything of substance on this wonderful Website!