The proper for an air squat is:

Mark each option as "correct form" or "incorrect form."
Correct form / Incorrect form
Knees should be in line with your second toe.
Hips push back.
Knees should come together.
Feet shoulder width apart.
Toes turned slightly out.

Correct form:

Knees should be in line with your second toe.
Hips push back.
Feet shoulder width apart.
Toes turned slightly out.

Incorrect form:
Knees should come together.