Add the frozen meatballs directly to the air fryer basket. No need to thaw.
Only put the meatballs in a single layer. Don't stack them or they won't cook evenly. if you can't fit as many as you want to cook then work in batches.
Set the air fryer to 375 degrees for 5 minutes.
Shake the meatballs in the basket.
Check the meatballs after 5 minutes. If they are browned and have reached at 165 degrees then they are ready. If not cook the for another 3-5 mintues.