Zones
Zones are created from areas of space inside a region. They can be created through the web panel by using two opposing corners of the cube you wish to define.
A character may be in only one zone at a time, if there is an overlap between zones, or one zone is inside another, the smallest zone takes precedence, this means you can nest zones, e.g. creating a large 'wilderness' zone but creating a smaller zone inside there that represents something of interest.
KVs can be assigned to zones which allows you to perform modifications based on location, such as changing attributes, or other configuration data.
In a multi-character installation of GPHUD you should consider creating a zone called OOC, and setting the “allow character switch” to true only in the OOC zone, this will prevent your users changing their characters anywhere else (assuming the default value remains 'false').
Zones are also used by the Event module to define the bounds of the event's location.