Complex sentence: The group stage will consist of two groups of eight teams, with the top four teams of each group advancing to the upper bracket of the best-of-three double elimination main event, and the bottom four advancing to the lower bracket.
Split into simpler sentences: The group stage will consist of two groups of eight teams. The top four teams of each group will advance to the upper bracket of the best-of-three double elimination main event, with the bottom four advancing to the lower bracket.