Here's some snapshots, they may help
I had some scrap stock and made a small set to show it can be done with one bit the norm that you have on hand,just about any bit will do the job , the top rail can be made many ways
It's best to use wide stock then put the edge (ends) on the stock then rip it to the right size then put on the other edges on..
Think Kreg pocket screws b/4 you mount it to the wall.it that way you don't have any nail holes to fill ,just lay it out on the floor, put in the pocket screws and then glue it to the wall
( liquid nails construction adhesive )
If you are going use bead board/plywood you will need to put on a rabbit edges on all the back side of the parts but that's a easy job on the router table
Here's quick way to setup the bit up just right,,use the center mark on the bit,make a pass on some scrap stock, about 12" long then cut it into two parts, flip one of them over, slide it together, it should fit just right if so you are set to run the rest of the stock,if not move the bit up or down just a little bit so it comes out flush, you don't want to do any sanding.. http://cgi.ebay.com/1-PC-1-2-Sh-Clas...d=p3911.c0.m14 http://cgi.ebay.com/1-pc-1-2-SH-Door...d=p3911.c0.m14