How to draw line diagrams in PS 7.0?

I am trying to draw a yard plan in PS 7 but am not sure how to do it. I am using the rectangle tool in "Paths" mode and even though it will draw a rectangle I cannot see it in the layer. Its all grey and when I hide other layers and just leave the rectangle layer open I cannot see it.
How can I do this? Also how am I able to adjust the line thickness?

Thanks.

hi there,
why not just use the rectangular marquee tool..stroke and adjust brush size...just a thought