CS4 Help.

in a lot of tutorials I am trying to do, it says make a rectangle box for example 477x447, but I don't see how to make exact measurements. Where does it show the dimensions? Also where do I add Custom Shapes? And what tool do I use to put them on my image? Thanks a lot, I am new. Everything else I seem to understand. I am using CS4. Here is the tutorial.

http://www.tutorialpark.com/effects/creating-business-style-template-design/

That's a very powerfull yet not that often used feature...
With the rectangle marquee tool selected, note the changes on the settings bar, just bellow the menu bar.
A drop box says: "Normal". Change it to "Fixed size" and input your desired size.
Now whenever you click on the canvas it will "draw" a marquee of that size.