How to add many-to-many relationship?

- First create two main tables with all required columns, and then add  third table (which is essentially empty [no columns]). 

- Now add relationships from both main tables to this table as shown in following image. 

    - Option 1: add identifying relationship (foreign key as primary key) hold CTRL button when creating reference.

    - Option 2: add non-identifying relationship, but add separate primary key for the table as best practice.

Option 1

Option 2