Place and Secure the Cabinets
Remove the doors from the cabinets for easier handling. Clamp the cabinets together (Image 1) to ensure that they're flush on top and along the front.
Using a bit narrower than the screws, drill pilot holes in the side frames of each cabinet, and secure them with wood screws.
Center the cabinets between the two side walls (Image 2).
Drill pilot holes through the bottom of the cabinets and into the base pedestal. Secure the cabinet to the base with screws. Remember that the base is recessed. Mark a line indicating the location of the base to help you screw directly into the wood.