The Top view should still be displayed. We will now zoom in to easily select the gripping surfaces and apply the constraints.
Navigate
Zoom
Window. Note that you can also access zoom commands from the Navigation Bar or use the mouse wheel to zoom in.
Selection
Shape
Point or Rectangle and
Select
Surfaces commands active, click and drag to draw a box enclosing the gripping surfaces, as shown in the following image. 
Setup
Constraints
General Constraint.