How Audience Guaranteed deals work via DoubleClick Bid Manager aka DBM

Here are the steps illustrating the ways buyer audience targeting is applied and forecasted for PG deals:

1. The publisher sends the proposal for buyer’s acceptance.
2. The buyer hits “Propose Changes” in their UI, and clicks into the line items in the campaign. Here, a new section for “Audience list” is displayed, where they can choose the lists they’d liketo apply to the line item.
3. Once done, the buyer “Sends Proposal” back to the publisher
4. The publisher will see the proposal as “In Review”. When the publisher clicks into the line items, they will see “Buyer has targeted/excluded audience lists” in the targeting section  but will not be able to see any information about the lists that were applied by the buyer.
5. The publisher can now run a forecast to determine how much inventory they have for the buyer’s targeting.
• DFP has real time access to the buyer audience lists (both during forecasting and serving). So, you can run a forecast to determine how much inventory the deal has for the buyer’s targeting and book the impressions according to the availability (for forecasting, DFP takes into account historical data and existing overlapping reservations for the future time frame of the campaign).
6. Then, the publisher selects ‘Request Acceptance’ to finalize the proposal terms with the buyer.
7. The buyer selects ‘Accept’ (in their UI) on the proposal.
8. The proposal in the DFP UI moves to the ‘Finalized’ state, and the corresponding DFP order and line items will be created in DFP’s ‘Delivery’ tab.

You can refer to these articles (article , article) which give a comprehensive insight around the audience targeting in PG.