Lay out the drop cloth and have your assistant help you stack the panels face up on the cloth. Be sure to keep the edges of the panels even on all sides all of the way up the stack. Use your tape measure to determine the middle of the ceiling and place a mark on that spot with your sharp point marker.
Hold the first panel against the ceiling just to the right of the center mark. Check for protrusions, measure them from the wall and from the center line, and record the measurement on the back of a panel for reference. Transfer the protrusion measurement onto the face of your panel, make the outline a half-inch larger than the actual obstruction, and cut the opening with your keyhole saw. Cut off the end or side of your panel if necessary for proper fit by laying the "T" square into place on the side or end of the panel and cutting off the scrap with your razor knife. Always make saw and knife cuts from the facing of the panel.
Apply an ample amount of construction adhesive to the back of the panel to be installed. Place a bead 2 inches from each edge, including cutouts. Place a crisscross grid of beads all over the back connecting the edge beads. Lift the panel into place and push against the ceiling to press all of the glue flat into the surface above.
Continue to measure, mark, and place the remaining panels to cover the entire ceiling. Continue to make your cutouts a half-inch larger than the protrusions in the ceiling. Allow the adhesive to cure for one hour before continuing.
Caulk around the edges of all of the panels and around each protrusion. Apply a bead of caulk and wipe it smooth with your finger. Keep your caulk gun and hands clean with a wet rag while caulking to ensure a uniform job. Allow the caulk to cure for one hour. Dispose of scrap properly. Enjoy your new ceiling.