If you've correctly specified inventory sizes in your proposal line item, there should be a one-to-one relationship between creatives in Display & Video 360 and the creative placeholders in Ad Manager.
You can then generate creative reports based on these placeholders.
The exception is video master/companion campaigns. While you can run video master/companion campaigns, Ad Manager does not collect metrics on companion ads hosted in Display & Video 360. As a result, Ad Manager reports won't capture delivery for companion ads in reporting for programmatic campaigns.
