Bond the 2 pieces of particle board with Liquid-Nails Heavy Duty adhesive. Apply in a zig-zag fashion over entire surface of the bottom board. Then spread it out at the edges with a putty knife to be sure of solid coverage of adhesive along the edge. A 1/4" bead at the edge will also work, but can get messy when it oozes out when the second board is applied.
Be sure the particle board is flat and on a flat surface. Then lay down the second piece of particle board on top of the adhesive. Lift slightly, set it back down and then align the two pieces so edges are flush. I'm assuming here that the boards are pre-cut to size and are matching. The weight of the top piece of particle board should be enough pressure to ensure a good bond. Let set overnight.
One other note: be sure the particle board and the laminate are at the same temperature before appling the laminate. Just leave the laminate in the same room overnight with the boards.