Complex sentence: Volunteer recruitment began on 14 November 2015, the same date as the launch party of the games logo, theme and mascot until July 2017, in which 50,000 people have signed up as volunteers.
Split into simpler sentences: Volunteer recruitment began on 14 November 2015, the same date as the launch party of the games logo, theme and mascot. Before July 2017,50,000 people have signed up as volunteers.