The Publications and Zones selection page allows the user to select one or more publications to advertise in. Publications in turn, may have zones associated with them.
The publications will appear in a list with a checkbox next to each publication. By checking a box next to a publication, you will be given the opportunity to place your ad in that publication. You will have an opportunity at a later date to add additional publications (or remove chosen ones).
If a publication has zones assigned to it, a list of zones will appear when you check the publication. You must choose at least one zone for any application that contains zones.