Some modes like Quick Play and Arcade allow you to pre-select your operators to load faster into a match. From the Fireteam Lobby screen, tap the button above the Game Mode button to enter the operator pre-selection menu. Select your preferred attacker and defender operators manually or use the Auto-Fill feature to select an order for you. Before the match starts, the game will try to pick your selected operators in order of preference, depending on whether another player has picked your operator before yours.