Complex sentence: The tournament start on May 11,2015, ended on May 24th, 2015 and will be played as a round-robin, so 15 rounds in total, each of which be micro-match from two games.
Split into simpler sentences: The tournament started on May 11,2015 and will end on May 24th, 2015. It will be played as a round-robin, with 15 rounds in total, each of which be micro-match from two games.