Step 1: Long story and parts used.
Some of the things I did have on hand were the 11.5" wide boards, some black "automotive" carpet and various wood screws.
Items I had to go out and purchase:
Two 8ft 3/4" PVC pipes.
Ten 90deg elbows.
Eight "T" fittings
Step 2: Sizing up the cat
I cut 2 boards out, so they are 11.5" X 22". Since my cat is old and fat, I figured I should make the perch with a lower level to help make it easier to get to the upper level that is at the window.