Here are the instructions to provide our agency with your Business Manager account access:
Click "Add Partner"
Insert our Agency ID # - 643319852534276
In the next window, assign us your Facebook Page, Ad Account and Product Catalogue (if applicable)
If there are any issues, you can always add us as an admin employee to your Business Manager using firstname.lastname@example.org
To make it even easier, here's a walk through video with me on how exactly to do this.