Sweater Pattern Help

So I just recently started knitting earlier this year and been working my way up from baby sweater to a sweater more my size but I most have chosen a way to complicated pattern for me since I’m already stuck on the first part. So Im hoping someone can shed some light over it and make me understand it before I start unraveling everything and try to find a new pattern.
hopefully I’m doing this right so you can see the attached picture. Its the whole “shape shoulders and back neck” that I don’t understand.

Thank you in advanced!

Welcome!
Good for you for working your way through baby sweaters and on to adult sizes. These kinds of directions are often confusing. You’re going to dec at the neck edge on the first shoulder and bind off at the beginning of the row for the shoulder shaping at the same time. Later you’ll get to shaping the other shoulder.
Start with the cast off of 4 sts (size small) on the RS row, work till you have 22sts on the right needle, turn. Don’t worry about the unworked sts. You’ll get to them later. On the WS row, work one stitch, dec 1, and finish the row. You’ll have 21 sts for that shoulder remaining.
You’re now onto a RS row, so cast off 4 sts, work to the last 3 sts, dec 1, work 1 and you should be at the end of the RS row. Now turn, work 1 st, dec, and work to the end of the row.
You’ll continue this way until you’ve completed all the decs and bind offs. Sometimes I make a small diagram showing these so that I can check them off as I go along.

Thank you! I think I got it. But I’m not sure if I’m suppose to cast off the stitches I put at the holder too?

You’re going to put some center sts that are on the holder onto another holder and work with the second shoulder sts. So slip the correct number of sts for the center neck onto a holder, join a new strand of yarn and work across the shoulder sts, turn and bind off the given number of sts for your size at the beginning of the WS row.