After choosing your creatives, go to How to distribute the ads? and choose One ad per set (1-N-1).

The 1st file goes only to the 1st selected ad set, the 2nd file to the 2nd, and so on. That's why the number of files and ad sets must match (3 files, 3 ad sets). The summary below the selector shows the math: "3 ad sets · 1 ad in each = 3 ads."

All ads in all ad sets is the default (2 files × 2 ad sets = 4 ads).

It works both on the files tab and on the Ad with Instagram Link tab, and also through MCP/Copilot (`create_ads_from_media` with `distribution: "one_per_adset"`).