Explanation:

Step 1: Open the relationship tab of the BusinessContracts entity.
View entity relationships
From the Power Apps portal, select either Model-driven or Canvas design mode.
Select Data > Entities and select the entity that has the relationships you want to view.
With the Relationships tab selected, you can select the following views:
Step 2: Select Add relationship..
Create relationships
While viewing entity relationships, in the command bar, select Add relationship and choose Many-to-many.
Step 3: Select the BusinessAccounts entity as the related entity.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/common-data-service/create-edit-nn-relationships-portal