Rule 716.5

While controlling another player, a player makes all choices and decisions the controlled player is allowed to make or is told to make by the rules or by any objects. This includes choices and decisions about what to play, and choices and decisions called for by spells and abilities. Example: The controller of another player decides which spells that player casts and what those spells target, and makes any required decisions when those spells resolve. Example: The controller of another player decides which of that player’s creatures attack, which player or planeswalker each one attacks, what the damage assignment order of the creatures that block them is (if any of the attacking creatures are blocked by multiple creatures), and how those attacking creatures assign their combat damage.

Find this number in the current Rules