Complex sentence: Starting with the 2016--17 season, the EuroCup's first phase is the Regular Season, in which 24 teams participated the participants included 24 clubs automatically entered into the Regular Season.
Split into simpler sentences: Starting with the 2016--17 season, the EuroCup's first phase is the Regular Season, in which 24 teams participate. The participants include 24 clubs automatically entered into the Regular Season.