A many-to-many relationship is a relationship between two database tables.
For example, a stuedent in university will have many teachers, and a teacher will have many students. The relationship between the two tables is a many-to-many relationship between students and teachers.
Adding a Many-to-Many
To add a many-to-many relationship first go to the table for which you'd like to create the relationship, then go to Develop > Add Many-to-Many.
At the top of the page, you'll see the table you selected, and a drop down list of other tables in your system. Select the table to which you'd like to add the relationship and then name the relationship. Usually something simple such as TeacherStudents or UserTasks is best.
Click create to add the relationship. You will see two links that allow you to view data in either of the tables.
View the Relationship
To view the relationship go to the detail view of any item in either of the two related tables. On the right hand side of the page, you will see a heading/link to the relationship. If there are related items, they will be listed below the link. There is also an add button so you can add new items.
Advanced - viewing all relationships in your system.
To see a list of all existing relationships, go to Develop > Many-to-Many.