If the unconscious person vomits, being in the recovery position will stop the vomit from blocking the airways. In the recovery position the tongue will also not block the airways. The correct recovery position keeps the patient steadily in a safe position.
This is how to turn the patient into the recovery position:
When the patient is lying on their back, bend the knee of the leg further from you at a right angle.
Place the arm of the same side across their chest and the arm closer to you on the ground pointing diagonally upwards.
Grab the person from the bent knee and the shoulder of the same side and turn them to face towards you.
Place the hand under the person's cheek and leave the knee bent as support.
Ensure the airways stay open by tilting the head backwards.