You enter the spirit realm. you cannot see anyone around you and they cant see you (unless they are in the realm with you). You leave behind a stationary "Husk" of yourself. Any attacks made on the husk will do nothing to you character but will alert you if its being attacked. At anytime you want or until the spell ends you can exit the spirit realm and attack with your weapon and gain advantage until your next turn. When walking around in the spirit realm creatures will feel a slight gust of wind which will alert creatures to your position. you can us ethis action after a short rest.