These are good sites to visit if you want to learn more about ADS-B.
AOPA Air Safety Institute’s online course, “ADS-B for General Aviation: The Basics.”
AOPA's ADS-B Equipage and Installation webinar (July 13, 2016)
FAA’s ADS-B Frequently Asked Questions
FreeFlight Systems’ ADS-B University
Garmin’s ADS-B Academy
Sporty's Pilot Shop's "ADS-B: A pilot's guide"