As of now, the set up of your Business Portfolio is manual. You will edit the Business Portfolio using Meta Business Suite > Business Settings UI. The user performing these actions needs to be an admin on the Business Portfolio.
Log into Meta Business Suite for your main Business Portfolio
Navigate to Business Settings for the Business
Create admin system user in Users > System users > + Add
Navigate to Application Console > App Roles > Roles. Copy the system user’s id, add it as Admin
Back in the system user management UI within MBS, click “Generate token” for the system user. Assign ads_management and business_management permissions
Copy and save the access token for the admin system user