Sand the surface of the particle board with 150-grit sandpaper. Wipe the dust from the surface with a tack cloth to remove the sanding dust.
Measure the face of the particle board and cut a piece of veneer 1/2-inch larger in all directions using a utility knife. Lay the veneer out with the back face up.
Shake your contact cement thoroughly to mix in the solids. Open the can and let it sit for several minutes until all bubbles clear from the surface of the cement. Pour a small amount of cement into a plastic paint pan.
Fit a medium-nap roller cover onto your roller handle. Roll the cover through the cement to load it with glue.
Roll a coat of contact cement on the particle board and on the back of the veneer. Turn on a heat gun to medium and blow it across the particle board and veneer backing to dry the contact cement until it is completely dry to the touch.
Lay 1/4-inch thick wood dowels across the particle board, so that they overhang each edge, one dowel every 6 inches.
Position the veneer over the dowel rods, so that it overhangs evenly on all edges. Pull the first dowel rod off of the particle board and press the edge of the veneer down, working from the center out.
Remove the next dowel and press the veneer into place. Continue working across the particle board surface, pressing the veneer down as you go. Use a wood block with well rounded corners to smooth the veneer into place. Working from the center out to press all bubbles from the veneer.
Trim the edge of the veneer using a utility knife. Press the blade down through the veneer against the edge of the particle board to cut it flush with the edge. Sand the edges smooth with 150-grit sandpaper.