To create a classroom you will start on your classroom Dashboard at classroom.google.com. Locate the "+" symbol in the top right corner and choose "Create Class."
You will need to title your class and fill in the "section" field (optional). Once you have set up the naming convention for your class click on the blue "Create" button.
From the Dashboard a user may also join a class at classroom.google.com Locate the "+" symbol in the top right corner and choose "Join Class."
A class code is required to join a class from this screen.
The instructor of a class would share this information with potential members of the class. This information is available in the "Stream" of any classroom.