Please review the forum post Creating a footprint in a round pin array
This should help you understand what needs to be done to create your round array of parts. If the origin of your footprint is not already centered on the part, you may want to do so before beginning. To change the origin of a footprint you will need to edit the footprint by selecting Design Edit Footprint. Determine the center point of the part and place a pin there. After placing a pin at the center point, right click on the pin and select Use Pin as Origin. Now delete the pin set as the origin and save your footprint. You are now ready to begin creating your round array.