The Trigger gizmo is used to trigger an event when you enter or exit a specified area.
To use the Trigger gizmo:
From Build Mode, select the Three Line icon, then select the Build icon.
Select Gizmos.
Grab the Trigger gizmo. You can now edit the properties by grabbing the gizmo and selecting the Three Dot icon with your controller.
Things to remember:
Each trigger can be activated by either players or objects, but not both. If Triggered By is set to Players, any player in the world will be able to activate the Trigger.
If Triggered By is set to Objects Named..., the Triggered by Objects Named field must also be filled out. This field can currently only take one name, and any object with that name will be able to activate the trigger.
Note that objects may only have one name (or one word as a name), but multiple objects can have the same name. The size of the trigger area can be adjusted by using the handles, just like the rest of the shapes.