i wouldnt want it to be this tall, and maybe have it have a second shelf too. just one? - This is as easy to build as it looks. Cut and treat your wooden board. Attach the horizontal piece to the vertical using glue and screws. Screw it to your wall.
I started doing this and will never stop! My tub shower are always spotless-so simple. Simple shower and tub cleaner: fill wand half and half. Wet surface and scrub. wow! leave in shower wash while you are already in there - This SO needs to be done in our bathroom.