This air fryer has only one knob to use. It is a timer, so you add the food to the fryer, plug it in, and turn the knob to the number of minutes needed to cook and you are done. I do wish the very small included recipe book had instruction on how to cook frozen and prepared foods such as precooked french fries, chicken nuggets or tater tots. I had to guess, and and the nuggets I cooked did not come out very crisp.