Pattern help

Knitting the front of a sweater with pockets. At point where I need to join the pockets. I confused on the instructions which follow :

Starting with 100 stitches on needle. (Ws) k9 place next 19 st on holder for pocket trim, then across pocket lining (already made and 24 stitches wide). Work [p5 M1 purl] 4 times p4 k next 44 sts, repeat ** for other pocket , k9 (118 stitches)

I am confused about what to do with the 19 stitches I put on a needle holder and how I attach the lining. Please help

The pattern vogue knitting winter2008/09 wintry whites cabled pullover. Picture in link

Thank you so much in advance!!!

Leave the 19sts on the holder. If you read ahead, perhaps to the Finishing, you’ll see directions for putting the sts back on a needle and adding an edging to the pocket top.
For now, take the directions for adding the lining step-by-step.
Knit 9, place the next 19sts on a holder, work across the 24 pocket sts (these must be on a holder or waste yarn or even another needle at this point) as follows: (p5, M1purl) 4 times, p4.
Then knit 44sts, and repeat the pocket lining 24sts with the second pocket as above; finally knit 9sts.
After this first row, the lining will only be attached by a single strand of yarn but as you continue the pattern, the lining will become more firmly incorporated into the knit fabric.

When I attach the pocket lining I’m working WS. Does the lining get attached with the purl side or knit side being the WS?

Thank you again!

Attach it with the purl side to the wrong side, that is, so that when you put your hand into the pocket, you’re slipping your hand along the knit side.

The pattern calls for a k1 selvage stitch on the RS. Do I knit it on the WS too or purl it

Thanks once again

You could purl it on the WS. I think it makes it easier to do a mattress stitch seam that way.
Beautiful sweater!