Note: Only a user with SuperAdmin permissions can access this.
As an Administrator navigate to the Courses option (1) and click on the little arrow below the "Add course" button (2). The "Copy from another domain" option will show up (3).
Type the name of the domain you want to copy from (4) and then fill in your username and password (5) to login.
After logging in to the second portal you will see a drop down with the available courses. Find the course you want to copy (6) and click on the "Copy course" button (7).