Ad IDs are assigned to each campaign item by the corresponding ad server as soon as the campaign item has been submitted to the ad server. Each campaign item then has this unique identifier to enable further communication between your ADvendio.com system and your ad server. So when you transfer further information to your ad server at a later point of time, e.g. when using the availability forecast, these pieces of information will be matched to the correct entries in your ad server.
Campaign Item Details
Since the Ad ID is displayed in the campaign item's details, you have to click the campaign item's name in order to be able to see it.
Ad Information
Ad ID data is stored in the section Ad Information. There you find the Ad ID. Depending on your ad server, the campaign item might have an Ad Server Order ID, too.