docs: Update UI Tools page for 3.1

Signed-off-by: wei.jin <wei.jin@thundersoft.com>

docs_src/getting-started/tools/Ch-GUI.md

@@ -156,7 +156,7 @@ After starting (or restarting) a service, you may need to hit the `Refresh` butt
 
 ### Metadata
 
-The Metadata page (available from the Metadata menu option) provides three tabs to be able to see and manage the basic elements of metadata:  device services, device profiles and devices.
+The Metadata page (available from the Metadata menu option) provides four tabs to be able to see and manage the basic elements of metadata:  device services, device profiles, provision watchers and devices.
 
 ![image](EdgeX_Metadata.png)
 
@@ -222,6 +222,12 @@ The `AssociatedDevice` button on each row of the Device Profile List will take y
 
     ![image](EdgeX_CantRemoveProfile.png)
 
+#### Provision Watcher Tab
+
+The Provision Watcher Tab on the Metadata page provides detailed information about all the Provision Watcher known to your EdgeX instance.  Buttons at the top of the tab allow you to add, remove or edit a Provision Watcher (or collection of Provision Watchers when deleting and using the selector checkbox in the Provision Watcher list).
+
+![image](EdgeX_ProvisionWatcherList.png)
+
 ### Data Center (Seeing Event/Reading Data)
 
 From the Data Center option on the GUI's menu bar you can see the stream of Event/Readings coming from the device services into core data.  The event/reading data will be displayed in JSON form.