Directions do not include specifications such as drain sizing, but very easy to assemble. This unit needs to be secure to the wall, which I accomplished with threaded metal wall anchors, threaded bolts, washers, and a wing nut (makes removal for cleaning under and behind fairly easy. If you want a flush-to-the-wall installation you will need to cut the baseboard behind the unit. I chose not to do so. You may also want to buy some small, self-adhesive pads because, while the soft-close doors do close softly, they make an audible "thunk" when at the end.