In order for an assigned ad to run, it MUST have an end URL. No end URL = no running. In your Ad Library, click on the ad you want to run and select Edit. There will be a dialogue box where you can put the URL.

Keep in mind:

• You can select multiple ads at once
• The system will automatically try to run the most size appropriate for the space of where you’ve put the ad unit. It will also automatically handle spacing for desktop, tablet and mobile.