When you create an ad, as soon as you click the Next button, a backup of your ad is done and if you do not finish it, it remains in your ads, in your personal menu.

An ad is considered incomplete until you complete the registration process, including payment for paid ads.

When you see your ads from your personal menu, if you see the Incomplete link (see picture) it is not yet finalized.

To complete your ad, click the Incomplete link, it will open a window at the step you were rendered and you can continue the process until it is published.