I have search the web for a pattern for courtyard steps. I want to make the blocks at least 12X12 when I am finished. I want the size of each strip to be about 3 inches wide.
Can someone direct me to instructions on how to make it this large.

Quiltbaby

Draw it out on graph paper. Three inch strips will give you 2-1/2" finished. Since 12-1/2" is not evenly divisible by 2.5, you will have to fudge the last rows. Otherwise, you can leave them full width, and have a different size quilt. Kinda-sorta sounds like you haven't thought your project out.

Why are you choosing 3"?

A great beginner log cabin book is Quilt in a Day Log Cabin by Eleanor Burns.

This is a 12 inch finished size courthouse steps block

The center is 2" cut at 2 1/2"
Each strip is 1" cut at 1 1/2"

This is also a 12 inch block
The center is 2 1/2 " cut 3"
Each strip is 1 1/2 cut 2"

The name of the pattern is Courthouse Steps (as in many steps). If you make your stripes 3" you will only get one and a partial step per side depending how large you make the center. (3+3+3+1.5+1.5)

If you want to make the wider stripe, I'd suggest a framed square.