Here's how many people are needed to play 'behind closed doors'

There is more to a top-level game than two teams, managers and a referee. When leagues resume, hundreds must be present for matches to take place.

source https://www.espn.com/soccer/english-premier-league/story/4085774/premier-league-games-behind-closed-doors-here-how-many-people-would-have-to-be-present