Although some patterns are obviously more advanced and harder than others, I do kind of think that when it comes to advancing skills you do just kind of have to jump in. There’s probably nothing between flat scarf and sweater neck shaping as an inbetween. …so just ask when you get stuck. Thia site is great isn’t it. I’m new too, learning from reading other people’s questions.
RS 52 stitches
Yes that’s it. You have used up 15 stitches.
If you have a holder use it for the 37, if not you can use a length of spare yarn, preferably in different colour to your working yarn, thread it through your stitches and tie the ends together so the stitches can’t fall off. You could even separate these stitches into two sets here, use a spare, thinner needle for the 15 that you are soon returning to as you are not going to leave them on hold got long. (Its OK to knit off of a thinner needle so long as your new stitches get worked onto the correct size.) And put the other 22 on a holder or yarn as they will be left longer and you want them very safe.
WS 9 stitches
Yes it looks like just cast off all 9.
The confusion by it saying 3 and then 6 might be that in a different size something else happens here (maybe look to see what a large size does, how many stitches and if it’s different to understand why the 3 and 6 instructions are separate)
You now turn back to the RS 37 on holder.
From the RS it will look like:
37 on holder, 9 cast off (remember this had previously been the 15 a row before when you cast off 6 and patterned 9)
What you aim for is:
15 on holder, centre 22 on different holder, 9 cast off (was 15 on previous row. This is why the centre 22 are the centre, making sense??)
Now you’re going to work the 15 in a similar way because this side of the neck is currently worked a couple of rows less than the other side.
Rejoin yarn to the RS of the 15 on hold and pattern to end.
You haven’t said the next part of the instruction but I would imagine you are going to cast off on the wrong side. Do check though. This would make the 2 sides of the neck an equal number of rows. The cast offs are sometimes on a different row but it won’t matter when you seam. Eg you might be told to cast off all 15 in one go on wrong side.
This leaves the neck centre 22 stitches in a holder.
Let us know if this helps or if you need more clarification.