There are two ways you can use this feature:
1. Tap once on the surface and drag the Push & Pull handler (make sure you're in a perspective view to see where you're dragging the handler to. You can also drag it in one of the default views.
2. Press & Drag a surface
To cut through extruded surfaces created using Push:
1. Create a closed shape on an existing flat surface
2. Tap to select the closed area and then use the Push&pull handler OR Pree & Push the closed area
3. Drag the closed area to the object's surface edge until you see the border of the closed is colored in Orange.
3. Release your finger or stylus to create the hole.