p3 (C4 p5) to last 9 sts C4 p3
k3 (p4 K5) p4 k2 p1
the next instruction is :
(dec row) p3 , patt 4, p2tog, patt to end
work 3 rows straight
Pattern 4 means to work the next 4 stitches in the established pattern. Since you are doing a cable and the first row you give says: "p3 (C4 p5) to last 9 sts C4 p3", you will be on a row like that one. So you P3, then the patt 4 will be where your cable is. Unless it is a cable twist row you would just knit those 4 sts. Then when you get to the first p5 you will do a purl dec by purling 2tog, then p3. Then when it says, "patt to end" you will go back to the established pattern which is (C4, p5) repeated, and ending C4, p3.
to last 9 sts C4 p3
This confuses me a little. Are you sure it doesn't say to the last 7? because it only gives directions for 7 sts not 9.
Pay attention to the numbers, but be sure you are not just doing it by the numbers but that the patterns you have established are lining up correctly.