To put the cabinets in place you need to drill holes -- two for the supply lines and one for the drain. Use a hole saw because the diameter is slightly larger than the supply line (Image 1).
Take measurements and make sure once the cabinet is flush against the wall the door won't be hitting a windowsill or frame. If you need to put the cabinet an inch from the wall, you can use fill stock to cover it. Remove the cabinet doors for easier access.
They measured in 1" from the wall, made a mark and then measured to the center of the pipe. Then, they measured up from the floor to the center -- transferring the marks to the back of the cabinets.
Start cutting from the outside of the cabinet and then finish cutting from the inside; that way if it splinters, the rough cut will be against the wall and no one will see it (Image 2).
After the holes have been cut, fit the cabinet over the pipes.
Once all the cabinets are in place, clamp them together at the face frame. Pre-drill pilot holes and then screw the cabinets together.
Note: Use the screws that are provided with the cabinet.
Check the level before you screw the cabinets to the wall. If needed, a few shims under the toe kick will get the cabinets right where you need them -- perfectly level.
Screw the cabinets into the studs using 3" cabinet screws. Use fill stock to take up the gap between the cabinet and the wall.
With a double-bowl vanity and drop in sinks, the installers left the sink cutouts in (Image 1) until they carried the countertop to the bathroom. It adds stability to the marble when they are carrying it. They then cut it out with a diamond blade saw. Note: A 5" diamond blade segmented for dry cutting was used on the cuts.
After the countertop was set in place, they used silicone to seal it in place.
Once they sawed the cutouts, they used double suction cups and a 5' aluminum rail to hold the cutout from falling through the hole (Image 2).
Once the marble countertop is installed, reattach the cabinet doors and drawers.