From your show's Detail Page, click on View Page next to the date you would like to reserve tickets.

This will bring you to the seat map/ticketing page for your event. Next, click on the seats you would like to reserve.

In this example I have selected M4 and M3. In the black Box Office Only box, select either Reserve or Box Office Comp.

By pushing Reserve, you are holding these seats for the ticket buyer to purchase at the door with cash or credit card. Please note: the total will say $0 because you are NOT taking payment now.

By pushing Box Office Comp, you are setting aside complimentary tickets that the ticket holder will not have to pay for.