If you leave the Ad Name field blank, the editor names the ads automatically, following the ad set's existing pattern. It checks the ads already in the ad set, finds the highest number in the ADxx pattern, and continues the sequence: if the last one was AD06, the new ones will be AD07, AD08, and so on. Each ad set has its own numbering, so the count can differ between ad sets. If you fill in an Ad Name and upload several media files, the system adds a number to the end of each name (for example, My Ad - 1, My Ad - 2) to tell them apart.