Casting off & Decreasing help

I’m having a little trouble understanding this decreasing tip for my sweater I’m working on.

This is the instruction:
DECREASING TIP:
Work 1 st as in diagram, work 2 sts tog, pass over the first st on needle = 2 dec sts.
Dec as follows in the different diagrams
M.1 (= 44-44-52-52-52-52-52 sts): 10-10-12-12-12-12-12 sts.
M.3 (= 8 sts): 2 sts.
M.4 (= 10 sts): 3 sts.
M.5 (= 16 sts): 6 sts.

It is for the back of the sweater to cast off before the collar

BACK PIECE:
= 118-124-132-142-160-168-178 sts. Continue back and forth on circular needle. Cast off to shape the armhole each side at beg of every row: 2 sts 2-2-2-2-2-3-4 times and 1 st 1-1-2-3-4-4-5 times = 108-114-120-128-144-148-152 sts. Continue in pattern. When piece measures 49-59-61-63-65-67-69 cm (adjust so that next row is row 7 in diagram M.1, M.3 and M.4) cast off, AT THE SAME TIME dec 24-24-26-26-36-36-36 sts in diagram on casting off row – see DECREASING TIP!

And when it says do one stitch as in diagram does that mean to do the cable stitch? And if so how do I do that.

I will post a link below of the pattern which includes the pattern diagrams.

These decreases are probably done to prevent the bound off edge from flaring. Don’t work the cable cross on this bind off row even though it is a row 7 in the charts. Work the sts as knits or purls as you decrease and then bind them off.
The work one stitch is referring to the fact that you need two stitches on the right needle in order to bind off.

So does that mean I just do one stich like in he pattern and for the rest of the row I just knit 2 and then pass over the previous stitch over that?

You don’t need to do that many decreases. The pattern says that you should decrease 24sts across the cast off row for the smallest size). The smallest size has about 118sts on the back piece after the armhole decrease. Under the Decreasing Tip, the pattern gives a number for the decreases over each of the charts. I can only get it to work out close to the 24sts required (again this is for the smallest size) but that may not be critical.
Work the sts as either knits or purls as you decrease if possible.