You now need to add pupils to the class. You do this by simply clicking on the pupils tile. This will add them to the class. To remove them from the class, click their tile from the box on the right hand side.
You can now name your class and assign it to a room. You have the option to create a new room, add it to an existing room or to not assign it to a room for the time being.
Then click the 'Create Class' button and you have successfully created a class.