When the MDM is configured to update your Asset Dashboard in Site Manager you can set the location for the devices.
Click on the Group, click on the user,
Click on the username box to edit the user
Click on the Set Location button
Click on the Choose Location radio button, then click on the set location drop down menu to select the location the devices will be set in the asset dashboard, press OK to complete the setting
You will now see the location selected on the User screen