[trvvn5]

Usually when something indicates the cable front or back the number in the listing indicates the total number of stitches involved in creating the cable. So a C4F means that 4 stitches are going to be involved in that cable. So you will slip two to the cable needle, move to the front, knit the next two stiches, then knit two from the cable needle. So in total 4 stitches were used, but only 2 were placed on the cable needle.

This used to confuse the crap out of me when I first started cables as well. If you're feeling daring, search online to find how to do cables without a cable needle. It's scary at first, but makes your knitting go much faster once you get the hang of it.