Navigate Here: Utilities > Custom Field Management > Browse Entities > Click the number in the Many-to-Many Relationship column of an entity
You can browse all many-to-many relationships of the selected entity on its Browse Many-to-Many Relationships page.
A brief summary of each relationship displays in the table. The summary includes Name and Other Entity.
Click the Edit icon 
of a relationship to go to the Edit Many-to-Many Relationship page of that relationship.