You're not dumb! Just inexperienced, but you're learning, so cut yourself some slack.
Yeah so, if you do one shoulder at at time, you're only working on half the sts, and that's all spelled out here -
1st row - K2tog, K35, P6, C4F, P3, turn.
Cont on these 49 sts.
2nd row - K3, P4, K6, purl to last 2 sts, P2tog.
3rd row - K2tog, knit to last 15 sts, K2tog, P6, K4, P3.
4th row - K3, P4, K6, purl to last 2 sts, P2tog.
Last 4 rows for patt for rem, noting dec.
The k2tog at beg of row 1 and 3 are the armhole edge, the p2tog at the end of row 2 is too.
Then on row 3, there's a k2tog 15 sts before the end and that's the V decrease. Looks like R 4 has another dec at the end for the armhole edge. Then keep repeating those 4 rows except you don't do the decs at the armhole edge anymore, and the dec at the neck edge will be every other row (5th, 7th...) until you have 36 stitches, then the neck dec will be every 4th row until 27 sts are left.