This image shows the popup window for the "Assign Users" menu option for the "DICS_ENTITLEMENT_ADMINISTRATOR" role.

There are four users listed:  Anna, Laleh and Jack with the member type of "Unassigned" and "DomainAdmin" user with the Member Type of "Direct".

The user "Laleh" has a checkmark in its checkbox, highlighted, suggesting you should select this user.

There is an "Assign" button for this window that's also highlighted, suggesting that you should click it.