Make sure that your Meta Business Suite is tied to your Facebook Business page and your Instagram Business page.
Make sure that you have an ad account tied to your Meta Business Suite. If you don’t, simply click “add”.
Make sure you have a Pixel by selecting Datasets > Data Sources. If you don’t, click Ad and name it the name of your business.
Once you know that you have all of these set up, go to Users> People. Click Invite People, and insert the emails for your CSM and your fulfillment partner. Make sure you grant full access to your FB and Instagram pages, your ad account, and your pixel.