How do I create an ammo counter?

In my game the players to over powered<so i want to add a ammo counter,a way to get ammo,and a way to make it so after they shoot they have to wait to shoot again.Help?

GIve your player 2 variables "ammo" and "cooldown"

when the player spawns, or picks up ammo, set his "ammo" variable to whatever you want.

set to starting value of the cooldown to "2" lets say.

event(3 conditions)

keyboard "on button press "space"

cooldown = 0

ammo > 0

action

create bullet at player.x, player.y

set cooldown to 2

event

every 1 seconds -> player.cooldown -1

This the player can only shoot if the cooldown reaches 0 and has more than 0 ammo

I just need help with the last part,every 1 seconds then what do i do

its a system event, look for it near the bottom

subtract 1 from the players "cooldown" variable.

i did subtract from cooldown 1 for every second and now i cant shoot

..maybe something like this ...