In the navigation bar at the top of the home screen, you will find a button labelled Teacher. This will bring you to the Teacher page.

In the top right of this Teacher page, you will find two different dropdowns. The first allows you to switch between your classes. The second is the MANAGE menu. 

Here you can do a few things:

Rename - Use this option to rename your class.

​Copy class - Use this option to copy an already existing class. Depending on your requirements of this new class, you can copy the Students, the Chapter, the Tests, or a combination of there.

​New class - Use this option to create a new class.

Archive class - Use this option to move your class to the Archive.

View archive - See the list of all the archived classes.

Faculty - Use this option to set the faculty that this class belongs to.

To create a new class, click on the "New Class" option. You can now give your new class a name. Make sure to save!

You will see that your brand new class now shows up in the first dropdown menu.

Find the existing class that you wish to copy to the list. Go to MANAGE and choose "Copy class".

When copying a class, you can also copy: Users, Groups, Course material, Tests, and Assignments.

More information can be found here.