Navigate to the cog at the top right of your account> houses section>create new house button.
You will be prompted with a pop up - please enter the house name and click save.
Your new house will now be available in the drop down menu. Once you have assigned students to the house manually or via an import, click on this you will be able to view students belonging to this house.
*Note: If you do not see a newly created house, make sure you have given yourself/your staff access to that house via the Staff section.