Help with edging on cardigan pattern


I am knitting “Patons Swingy Cardigan” and I have a question about the left and right front cable edging, specifically how to “sewing in position as you knit”.
Left Front Cable edging: With pair of needles,
cast on 14 sts.
1st row: (RS). *K2. P2. Rep from * to last 2 sts. K2.
2nd row: P2. (K1. M1. K1. P2) twice. K2. P2. 16 sts.
3rd row: K2. C6F. C6B. K2.
4th row: P16.
5th row: P2. K12. P2.
6th row: K2. P12. K2.
7th row: K16.
8th row: P16.
9th to 12th rows: As 5th to 8th rows.
13th and 14th rows: As 5th and 6th rows.
Rep 3rd to 14th rows for pat until piece (when
slightly stretched) measures length to fit up
Left Front edge, across top of Left Sleeve and
across to center back neck edge, _sewing in _
position as you knit. Cast off in pat, dec 2 sts
evenly across as you cast off.

Thank you for any help!


Seaming the edging to the fronts helps you determine exactly how long the edging should be. You can wait until you’ve knit most of the edging, leave the live sts on the needle and then seam. That way you can determine exactly how much further to knit to reach the center back.
You can use mattress stitch or a Bickford seam for this:


Thank you so much, salmonmac!