The wait command is one way, or you could add a timer to your player, which increases/decreases each tick/every x seconds or whatever, and then you can only shoot when the timer has reached a certain value. E.G
Every tick : Player.ShootTimer - 1
On key press :
Player.ShootTimer <=0 : Shoot
: Set Player.ShootTimer to 30
That's a coding approach, but the wait command should do the trick anyway.