You can add a default service technician to a building, so that any work order created for this building will automatically be assigned to that tech.
To do this, first navigate to the building.
Then, click to edit the building.
In the "Details" area, you will see two dropdowns: Default Inspection Technician, and Default Service Technician.
The technician selected here will automatically be assigned to any inspection, or work order, at the building.
However, when you are creating a new inspection or work order, or editing an existing one, you can change the technician selection as needed.