What is “Add new ad” and how does it work?

From the Campaigns view:

1. Select one or more existing campaigns.
   
   
2. Click Add new ad.
   
   

This opens a special update draft that:

• Shows campaign information (read-only).
  
  
• Lets you add new ad groups.
  
  
• Lets you add new ads to existing or new ad groups via the usual Assets and Ad builder steps.
  
  
• Uses the same verification and preview steps.
  
  

Differences compared to full drafts:

• Campaign settings (objective, high-level budget) are not editable here.
  
  
• In the Preview step, the button is called Publish updates instead of Create campaigns.
  
  
• The changes you publish are incremental:
  
  
  • Only the new ads/ad groups are pushed.
    
    
  • Existing campaigns and ads remain, unless you explicitly modify them.
    
    

Errors and Pending work the same way:

• The update draft can go through Pending and Error.
  
  
• Errors usually relate only to the new ads/ad groups.
  
  

You can delete this kind of draft without deleting the underlying live campaign (you’re just discarding the update attempt).