Learn how to sail first. Take some classes and get some time in. Getting any of the Captain's licenses is going to take a lot of time. I believe it is almost a year's worth of sailing on federally regulated waters. Not the local lake on that..... Go to the American Sailing Association or US Sailing websites and find a school to get some lessons. You obviously are going to need a boat to sail on as getting the necessary time for USCG Captain's Licenses is kinda tough to do via charter. Its not just book work. Try these links;
Six Pack Classes
Google is your friend..
And this place is a great resource too.........