6 - Now create these Planes. Click in the left view and front view window and create the sides where the boxes will collide with each other make sure you have also created the floor too as the picture below shows.
7 - With the Reactor Plane still selected, create once more another one in the top view and then move it upward over the lamp indicating below in the picture.
8 - When you fix the upper Plane to the lamp light exactly, now go to the Reactor panel the choose, Spring as image below shows.
9 - Now check the parent box and then click on the None button, then hit the lamp light. In the Child choose Plane and also set the Dynamic Properties like the picture below.
10 - Your objects should look like in the image below.
11 - Ok, go to Utilities - Reactor - Preview & Animation tab then change the settings like in the image below.