Attach the vanity to the wall using 3 inch drywall screws.
Attach countertop to half wall.
If the holes are not completely lining up or you want a more secure install use wall anchors to attach the vanity to the wall.
If you attach a countertop to the wall with absolutely no cabinets whatsoever then use the same bracing techniques on both sides.
Using a utility knife cut the cardboard along the scribe line.
If you re working with bare plywood or particleboard place nails vertically down through the top of the countertop spaced about 4 inches.
The point where two counters meet in a corner must be square.
For a tight fit screw the angles to the cabinet first and then draw the top down to meet the steel angle with the second screw.
Push the strip back tight against the wall using the combination square to verify the overhang depth.
Seal any gap between the backsplash and the wall or along the edges and the wall with a clear silicone acrylic caulk.
Check the level again before trimming the shims with a utility knife.
Steel angles with 5 8 in.
When you measure for your countertop be sure to include the counter overhang which is usually between 3 4 1 inch in front and on open ends.
Make a mark 3 feet from the corner on one wall and 4 feet from the corner on the other wall.
Screw the countertop to the cabinet sides using 1 1 2 in.
Slide the end of the countertop over the horizontal stud.
Retape the strip in place.
The fascia laminates and backsplash can now be added.
Cut the boards 2 inches shorter than the depth of the countertop with a circular or table saw.
Attach three 1 inch by 4 inch wood boards to the wall brace board to hold the countertop.
Be sure to place pressure sticks along the back corners where the corner blocks are located to get the countertop down tight.