David Ellcock explains the different roles at a tournament, when more than one official is appointed

The lead official is called the tournament director, or the technical delegate for international events. This is the person usually referred to as the TD. They are in overall control of the tournament. They ensure that all teams have registered their players correctly. They confirm the teams’ kit colours and determine what colours the teams will wear for each game. They appoint the technical officials to each game and work with the umpire manager to appoint the umpires.