It helps if you break it down.
Slip marker, k 1, CO 3 sts (I don't know that purlwise is necessary) you then have 143 or 164 or 178 or 192 sts on the needle, depending on the size you're making.
Then turn and work flat (not in the round). Work 3 rows in the stitch pattern but make 4 sts on the right edge of the neck and 1 st at the left in garter st.
The next row is a dec row and you k1 sl 2 sts to cable needle, hold in back and k1 ssk from the left needle, then k2 from cn, and p2. Rep from * 18 (21 23 25) times more then sl 2 sts to cn and hold in back, k1 ssk on the left needle, k2 from cable needle and end with k4. You have 123 (141 153 165) sts on your needle and work 3 rows in the stitch pattern.