Face Buttons
The "1" button is for the "use" function and "move closer to survivors" when playing as an unspawned Infected character; "2" is for jump; "3" is used to "reload"; "4" is used for selecting weapons. The secondary function for "1" is when playing as Infected.
Triggers and Bumpers
"L1" is used to crouch, and "L2" is used for the secondary melee attack, which is usually a gun butt or swipe when playing as the Tank. "R1" is used to do a quick 180-degree turn, and "R2" can be used to fire your primary weapon or do your primary attack. When playing as Infected, "R2" also spawns the character in the world.
Analog Sticks and D-Pad
Left Analog Stick moves your character and Right Analog Stick looks around to aim. The D-Pad is only used for "Survivor" functions. "Up" activates the flashlight, "Right" uses First Aid Kits, "Left" uses Pain Pills and "Down" uses a throwable item like Molotov Cocktails.
Other Buttons
The "Mode" button switches primary control from Left Analog Stick to D-Pad, which isn't recommended for this game. The "Select" Button brings up the Status Screen and votes "no," when a kick vote or map vote appears. The "Start" button brings up the Main Menu and votes "yes" in polls.