Earlier in the pattern, you marked the sides of the sweater and then put in another marker at 6,8, or 10 knit sts depending on the size you are making. Now the instructions are to knit to the marker and then knit 5 more sts ("Work 5 sts beyond the first pocket marker"). In other words, knit 11,13,or 15sts from the side marker. This is where you start to join the pocket sts that you've worked on until they were the same length as the main body of the sweater. To do that, hold the pocket sts on a needle in front of the main body sts, both needles in the left hand and knit two sts together, one from the pocket, one from the main body.
It's a very sweet, cozy sweater. Enjoy knitting it!