Complex sentence: They are charter members of the National Arena League, founded in 2016 and was a part of the Arena Football League (AFL) from 2010 to 2016 and won the championship of their division in the first four seasons of their existence.
Split into simpler sentences: They are charter members of the National Arena League, founded in 2016. They were members of the Arena Football League (AFL) from 2010 to 2016 and won the championship of their division in the first four seasons of their existence.