How do I use a dedicated mini?

When you have a miniature (commonly known as a "mini" or "minipet") in your inventory or storage in Guild Wars, you can double click on it to activate or deactivate it. When active, a miniature will follow you around, but will not affect combat in any way. You can only have one miniature active at a time, and no miniatures will be active when you load into an instance.

There is no miniature inventory in Guild Wars, but they can be placed in any inventory or bank slot, except for equipment packs.

All miniatures are initially undedicated ("unded"), and can be added to the Devotion monument in the Hall of Monuments ("HoM"). Once a miniature has been dedicated to any character's Hall of Monuments, that miniature is permanently marked as "Dedicated" ("ded") and cannot be added to another Hall of Monuments. Dedicated miniatures can still be traded and used by any character.

There is no mini inventory in Guild Wars 1. The only thing you can do is having your mini in your inventory and double-clicking it to make it appear in your instance.