Purchasing a House
Look around the city for houses with tag "For Sale". Once you find a suitable house, use /buyhouse [ID] to purchase it. The ID of the house can be found in the house description
Controlling your House
To control your house, you must be inside one. Use /housemenu to browse through the various functionalities available like upgrading interior, managing locks, managing house-spawn, setting house for sale, etc.
To enter/exit a house you can use ALT key in checkpoint
There various house alert systems available ranging from simple Alarm to Secure Locks that can be purchased to protect your house from being robberies.
If you have more questions feel free to use /ask