Invite SourceMedium as a member to your TikTok Business account
From your TikTok Business account, navigate to Users > Members > Select Invite Member
Add integrations@sourcemedium.com as a new member and select Standard access settings. This will send an email to inviting SourceMedium to connect your data
Once you have approved Standard access for SourceMedium to your Business Center:
Go to your Business Center and click Ad Account under Assets
Select the member (SourceMedium) for whom you want to edit permissions to ad account