Go to the USCG site for Licensing:
http://www.uscg.mil/STCW/
This will give you all the information and forms for obtaining your first license.
It is true you can get a OPUV License (six pack), but I recommend you also request the 100Ton Mate license at the same time (has same requirements and test. Once you add the additional sea time, you can get an upgrade to (upto) 100 Ton master license. This license will allow you more opportunities and the ability to operate inspected vessels, you never know what opportunities will arise!
There are many license prep courses out there and courses with testing included.
Go Luck!