Shaping Armholes in a Sweater Vest

I am knitting a sweater vest and will need to start shaping the armholes soon. The directions say:

"Bind of 6 stitches at the beginning of the next 2 rows, 78 stitches. Decrease 1 stitch every Right Side row 10 times- 58 stitches. Work even until armholes measure 9 inches, end on Wrong Side.

To Shape the armholes, bind off 6 stitches at the beginning of the next two rows, then 5 stitches at the beginning of the next two rows. Bind off remaining 36 stitches for the back neck."

How do I know which is WS and RS? Will I decrease 1 stitch every other row then when it says to decrease 1 stitch every right side row? I’m just not sure I am understanding it correctly.

It then goes on to explain how to knit the front. So I will basically end the front and back with two separate knit pieces that I will sew together (as explained in finishing section), right? Just making sure I am understanding this, as this is my first sweater.

Here is the link to the pattern: http://www.berroco.com/patterns/peter-easy

Thanks!

This vest is worked in stockinette stitch so the side with the Vs is the RS, right side (or public side). Yes, you’ll be decreasing one st [I]each edge[/I], every other row (that’s one stitch near the right edge and one st near the left edge) on the RS rows. And yes, you’ll be knitting two pieces which will be seamed together at the end. I’ve re-inserted the full directions.
"Shape Armholes: Bind off 6(6-7-8-9) sts at beg of the next 2 rows – 70(78-86-92-100) sts. Dec 1 st ea[I]ch side[/I] every RS row 8(10-11-12-14) times – 54(58-64-68-72) sts. Work even until armholes measure 8 1/2(9-9-9 1/2-10)”, end on WS.

Shape Shoulders: Bind off 5(6-7-8-9) sts at beg of the next 2 rows, then 4(5-7-8-9) sts at beg of the next 2 rows. Bind off remaining 36 sts for back neck"