About a pattern!

Hi everyone!
This is my first posting. I am a beginner for knitting. I am making a men vest sweater. There is some instructions that I don’t understand. Can everybody explain clearly to me?

Here it is:
[B]Shape armhole:[/B]
Bind off 4 (4,5,5,5) sts at beg of next 2 rows. Dec row (RS) K0 (0,1,1,1), p1, SK2P, work in pat to last 4 (4,5,5,5) sts, k3tog, p1, k0(0,1,1,1). Rep dec row every 4th row 1 (2,2,2,2) times more-55 (55,57,61,65) sts. Work even until armhole measures 8 1/2 (9,9 1/2,10 1/2,11)"

[B]Shape shoulder[/B]
Bind off 4 sts at beg of next 8 (8,6,4,0) rows, 5 sts at beg of next 0 (0,2,4,8) rows. Bind off rem 23 (23,23,25,25)

Hope to hear from everybody soon.
Have a nice weekend.
Thanks everybody!

Hi and welcome!
What in particular are you having trouble with? Which size are you making?

Thanks for your replying.
I am making a medium size. I don’t understand about " bind off 4 sts at beg of next 2 rows. And what is dec row (RS)? And “rep dec row every 4th row 1(2,2,2,2) times more”?
Thank you again!

OK, you should have the right side (RS) or public side of the knitting facing you. Bind off 4sts, knit to the end of the row, turn to the wrong side (WS) or private side and start the row by binding off 4sts, then work in whatever stitch pattern you’re using to the end of the row.
The next row is the decrease row (Dec row) and you should be back to the RS row for these decreases.
Once you’ve completed the decreases row, turn and work the WS row. The instruction is the repeat the decrease row every 4th row twice more. So work across the RS and WS rows again without any decreases and on the next row, a RS row, repeat the decrease row. Work the WS, RS and then WS rows and finally one more decrease row.

Thank you so much!
I have one more question: I am using “mock rib st” to knit. So when i bind off 4 sts, then I need to knit to the end of the row or I need to use “mock rib st” to the end of the row?

Mock rib st:
RS: p1, *wyib, sl 1 purlwise, p1, rep * to the end of row.
WS: purl

Have a nice weekend!

Keep knitting in the pattern stitch, the mock rib. You’re going to continue until a certain measurement and then bind off for the shoulders so unless the directions say otherwise, keep doing the mock rib.
Thanks and enjoy the weekend and knitting too!