It's easy! PADI Discover Scuba Diving is a quick way to get you in the water, experiencing what it is like to scuba dive.
If you enjoy it, and I have no doubts you will, you can take the next step, and become a PADI certified diver. Why would you want to do that? We will teach you skills that will help your dives be longer, more enjoyable, and safer.
There are a few different organizations that will help you certify. I happen to work with PADI, the largest one. PADI Open Water course gets you to the first level of certification - PADI Open Water Diver (makes sense, right?)
In addition to online learning, you will spend about 10 hours in the pool (usually split over two days), as well as two days in a lake, ocean, sea. You can do both locally, or you can choose to do the pool part close to your home, then finish the "open water" days on vacation.