Popunder is an advertising format with the following feature: the advertiser's site opens in a new browser window after the user clicks on any area of the page where the ad is placed. The advantage of this format is its low cost per click.
For this ad format, the CPM (cost per thousand impressions) payment model is not available.
A Popunder campaign does not require adding ad creatives — the campaign itself acts as the creative. Impressions begin immediately after moderation.
Balance: A Popunder (Clickunder) campaign is active only if the balance is more than $10. If the balance is $10 or less, the campaign will not receive impressions.
Since no separate creative needs to be added, follow the standard campaign-creation procedure described in the guide to creating an advertising campaign.