To manage an advertiser's team and settings, select the advertiser from the dropdown at the upper right.
Edit Advertiser Team
You can then click on the team tab at the bottom of the page to edit, add and remove team members who have access
Note, users with admin permissions are granted access to all advertisers by default. To remove an admin users from an advertiser account you must change the user's permissions by selecting Users + Permissions from the gear dropdown menu in the upper right of the page.
Click the check boxes to select or deselect team members from the advertiser's account.
Click Save to submit your updates.