To install upper and base kitchen cabinets, mark their position on the wall, and locate the studs. For upper cabinets, attach a support board to the studs. Screw a few cabinets together, pre-drill on the studs and framing piece for screws, and attach cabinets.
Begin installing the upper kitchen cabinets by measuring their position from the floor to the cabinet's base. To install the base cabinets, start with the corner unit and at the highest floor point. In both cases, mark the cabinet position. Ensure that the line is horizontal with a level. Identify the wall studs using a stud finder, and mark them using vertical lines.
To install the upper cabinets, screw a support rail or ledger board on the studs. The support board is not necessary for base cabinets. Remove the cabinet hardware and doors, and attach a few cabinets together at the stile and along the side where their sidewalls meet.
For the upper cabinets, position the cabinets on the support board, check if the level and plumb are correct, and shim, if required. For the base cabinets, dry fit them, and shim, if required.
To secure the cabinets, drill into the top, thick framing strip and the studs, and affix the cabinets using wood screws. Position the upper cabinets with their base on the support board's top edge. Attach cleats or wood pieces to cover gaps between countertops and base cabinet tops. Finally, replace the cabinet hardware and doors and remove the support board.