Place a ladder under the section of the ceiling where the panel will be installed. Measure the proper width and length for the panel.
Lay the ceiling panel on a flat surface with the finished side down. Transfer the proper dimensions onto it.
Press a straightedge firmly on top of the pencil line with one hand. Move the blade of a utility knife along it to cut the ceiling panel, approximately 1/4-inch deep but not all the way through.
Slide the ceiling panel over the edge of the table so the pencil line hangs off by 1/2 inch.
Hold the ceiling panel firmly on the table with one hand and snap the free edge downward quickly with the other hand to break it off.