Each time the entity attack, a cooldown start so it cant attack

Im making a custom boss, that uses geckolib animations, i succeed with the damage procedure, but now i have a problem : whenever the boss get close to me, instead of attack once, then start the other attack, it just spams all the existing attacks as soon as he makes contact with the target.

What i want to make is, for every attack, a cooldown starts so the boss cant start any other attack untill the cooldown ends.

If you have any answers, please share with screenshots for easier understanding.

Thanks in advance.