cooldown timers

How exactly can I make it so I can setup a cooldown system. Not exacly sure how to use timers in unity but I believe it would be pretty simple.

 if(Input.GetKeyDown(KeyCode.Alpha2) && cooldown1timer == false) {
 
 cooldown1timer = true;
 
 
 //start timer to change cooldown1 to false again after 10 seconds
 
 }