How do I add spell cooldown?

Hi, i'm making a game with spells but i don't know how to make a cooldown for them

example :

i press p to shoot a bullet

i have to wait 10 sec

then i can press p again and shoot another bullet

Use Timer behavior on the player. For example, when you cast a spell, set variable SpellEnabled=false and start a timer "cooldown". On timer event, set SpellEnabled=true

Do i need to add a instence variable to the player or global variable

You can use instance or global, it's up to you.