Rows Help Sandbar Pullover

I looked up the tuck st to see how it’s done, so that’s not a problem, but what I did was start with the “Setup Row” and then go straight into p a row ans k a row until row 6 where I did the tuck to make holes. Then from there I went with Row 1 of the pattern and cont’d until Row 4. Then I got stuck. When and how do I start the tuck stitch over again? Am I supposed to do the whole panel in tuck st pat? If so, then when do rows 1-4 come in? Also, what does it mean by “(multiple of 2 sts + 3)”?
Work in tuck st pat until back measures 15½
Tuck st pat:
(multiple of 2 sts + 3)
Row 1 (RS): K1, p1, *yo, sl 1
p-wise wyib, p1; rep from * to last
st, k1.
Row 2 (WS): P1, k1, *sl st and yo
p-wise wyif, yo, k1; rep from * to
last st, p1.
Row 3: K1, p1, *k next st and 2 yo
tog, p1; rep from * to last st, k1.
Row 4: P1, *k1, p1; rep from * across.
Rep Rows 1-4 for pat.
PS: I’m thinking this may just be too complicated for me, but I wanted to ask before I give up.
TIA

Welcome to the forum!
What is the name of the sweater pattern you’re following?
Rows 1-4 give you the pattern stitch. The directions for the back will tell you how to work the pattern stitch as part of the sweater. It looks like the tuck stitch repeats (rows 1-4) up the entire back. The photo should confirm this.
Multiple of 2 + 3 tells you that if you want to increase or decrease the number of sts you need to inc or dec by two’s, i.e. 2,4,6 or 8 etc. There are 3 extra sts needed for the pattern. So 23sts or 25sts or 27sts would work. The directions for Casting On will take this into account.

It’s the Sandbar Pullover. When I did rows 1-4 the # of sts kept increasing. It makes sense that the back would be done in tuck st pat, but not rows 1-4, so I wonder when rows 1-4 come in. I might just not bother with this one.