Organization management has a nice widget called assignment coverage tracker that helps you see what percentage of brands have buyers assigned against them. Using the tracker, you can see which teams have not yet put in the buyers buying from those brands. You can see what this widget looks like below.

As you can see in this list, luxury teams have specified a buyer for almost all of their brands. However the premium teams are missing some of the user assignments. To see specifically which brands don't have buyers against them, click on the appropriate tracker, specifically Mens / Premium  team as an example.
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You can see here that brands for 61.3% of the budget and the 72.5% in terms of count do not have buyers assigned to it. You can click on this pop up to see the list of all brands without a buyer assigned sorted by its budget in a descending order. Using this list, you can see all the  Mens / Premium  brands without a buyer. If you are then the buyer for any of these brands, please follow the steps here to add these brands to your assignments.

Once you update your user assignments with the unassigned budgets, you should see the progress on the user assignment coverage. The goal is to get to 100% coverage for all the brands with a budget.