Roblox Studio How do i force equip a tool and unequip?

I've been looking in the internet for equip a tool. Saying like when a key is pressed, i know how to do that but im not sure how to equip a tool and unequip a tool from what the player is holding. So im trying to do if this key is pressed then equip tool. Then when the tool is equipped and the key is pressed then unequip a tool. Im not sure how can i unequip and equip a tool