To create a class, log into Teacher Dashboard and go to the Classes page. If you have the permission to create a new class, you will see the button underneath the Classes page title.
Click on the New button and you will see the add classes popup window where you can add a name and a description so that you can identify it later.
If the class has been created, you will see a success message and see the Details, Advanced and Members tabs.
If you only have the role of 'Teacher' within Teacher Dashboard, when you click on the Advanced tab, you will not be able to change the school that the class belongs to and so the 'Remove from this school' button will be greyed out.