Filter your inventory. Go to the Inventory page and filter down to the units you want in the flight.

Select the units using the checkboxes.

Click Actions in the top navigation bar, then Add Flights.

Set Flight Type to Booked.

Choose the advertiser. If it is not in the dropdown, click Add New Advertiser, type the name, and click Create Advertiser. It then appears in the dropdown for selection.

Choose the campaign. Pick an existing one, or type a new name and click Create.

Assign an Account Manager from the dropdown.

Set the flight dates. Pick a Start Date from the calendar, then either choose an End Date manually or use the duration buttons to set it automatically.

Add a 4-Week Price if you want one. This is optional.

Click Save to create the flight across every selected unit, then Close to return to your inventory list.