Add instructions for opening a scene in Creating instances (#9143)

Co-authored-by: Hugo Locurcio <[email protected]>

getting_started/step_by_step/instancing.rst

@@ -114,8 +114,12 @@ There is more to instances. With this feature, you can:
 .. note:: Changing a property on an instance always overrides values from the
           corresponding packed scene.
 
-Let's try this. Open ``ball.tscn`` and select the Ball node. In the Inspector on
-the right, click on the PhysicsMaterial property to expand it.
+Let's try this. Double-click ``ball.tscn`` in the FileSystem to open it.
+
+.. image:: img/instancing_ball_scene_open.webp
+
+Select the Ball node. In the Inspector on the right, click on the PhysicsMaterial 
+property to expand it.
 
 .. image:: img/instancing_physics_material_expand.webp