I have two tanks I use to scuba dive with, or did you mean the other kind? I just have one of those!
The first step is to go to your local dive center (or a few places if you're lucky to have more than one) and find an instructor that you are comfortable with and get certified. The class involves some classroom time, pool time, and some time actually diving with an instructor to go over the essential skills in a real-world environment.
After you're certified, my best advice is to work with your local dive center on places to go. They will probably have regular trips to nice warm tropical destinations with beautiful reefs. IMO, this is best route to go because they have a lot of experience knowing where to go and they've likely been to that same place several times before so they know its good. Believe it or not, but there are a lot of poor to just below average places to dive even in places like the Caribbean that would surprise a lot of people who don't know better. There are a lot of truly amazing places too, too many to list really. Your local dive center will also bend over backwards to make sure you have a good experience because they want to keep you as a customer.
Good luck, and have fun!
