The hardest part to installing a metal panel ceiling is the preparation. You need to remove all light fixtures, locate all of your ceiling joists and mark them. The existing ceiling is covered with plywood cut to fit the ceiling. Plywood is heavy, and it will take two people to hold the plywood while cutouts are made around electrical boxes or other features. Remember to make any light fixture alterations before you install you plywood. Making changes later will be difficult.
Mark your ceiling joist locations on the underside of the plywood. Using a different color of marker, measure and mark the layout of your metal ceiling tiles. Most tiles are square, but they are sold as individuals and as sets of four or more. Lay out your pattern so that none of the seams of the metal tiles will line up with the seams of the plywood. Draw the entire layout on the ceiling.
Start installing your panels furthest from the entrance to the room. Two edges of each panel will overlap adjacent panels. This means you nail the edges furthest from the entry door and overlap the edges so that you cannot see the overlap from the door. Practice with a few tiles on a table until you see the direction you want. Nail the panels to the plywood, aligning your panels with your ceiling drawing as a guide. Use the nail size recommended by the manufacturer. The panels are nailed along the edges with the nails hidden inside the design of the panels.
Cut holes in the metal to fit around electrical boxes and other features. You can usually cut the holes with tin snips or a small rotary tool with a metal cutting blade. All of the body of the ceiling should be installed before trimming the edges. Look for decorative edge treatments used to cover the edge of the metal ceiling and the corner. These pieces also overlap each other and should be installed so that the overlap hides the seam from the entrance to the room. Miter cut your corners or use the precut corner pieces sold for your ceiling.