How do you do Basic Life Support on a prone person?

Suppose you walk along a street and you find a person lying prone. How do you go about assessing and managing the patient using the Basic Life Support (ABCDE) protocol? As far as I am aware, you are not supposed to move the patient from the position that they are in. But then how do you check the airway? How would you do a chin lift and jaw thrust? Etc.