First sweater collar

Hi, I’m just about complete my first sweater. All that is left is to knit the collar and assemble. I don’t exactly understand the wording in the pattern.

RIGHT HALF OF COLLAR

Join shoulders.

Using 3.75mm needles, cast on 28[28:28:32:32:32] sts.

Work 2 rows in rib as on Front.

NB: If you need to join in yarn, do this at the shaped edge.

Taking extra sts into rib shape neck edge by inc 1 st at beg of next row, then at same edge on every foll alt row until there are 40[40:40:44:44:44] sts, then on every foil 4th row until there are 43[43:43:47:47:47] sts.

Cont shaping neck edge.

(NB: On Left Half now work 1 row straight.)

Next row: Rib to last 3 sts, turn.

Next row: Sl1 firmly, rib to end.

Work 4 rows in rib on all sts.

Rep last 6 rows until shaped edge fits up side edge of front neck and round to centre Back of neck.

Cast off loosely in rib.

So what I understand is that I’m joining my front and back before starting. But am I picking up stitches for the collar? The pattern says cast on not pick up. But based off the photos in the pattern (http://knitted-patterns.com/knitting-for-men/pullovers-sweaters/3895-mens-jumper-free-knitting-pattern) I believe I am picking up stitches and then sewing the sides and back into place.

Am I increasing 1 on the attached edge or on the open edge?

Sorry I am really quite confused about the wording. I appreciate any help. Thank you!

This collar is worked separately and then sewn onto the sweater. It may help to read the directions for Finishing to see how it attaches to the sweater.
Cast on the required number of sts and work the increases on the edge that attaches to the neck of the sweater. Add a marker near the edge so that you can easily remember which edge that is.

Thank you. The actual seaming directions doesnt include much. I will be wat hinf youtube for instructions.

Actually it working sepearately makes me really happy. Thank you again. But why does the instructions bother telling me to attach at shoulders becore casting on?

Probably so that you can measure the length of the collar around the neckband to the back.
These collars work out very well. Enjoy!