Pattern help

Please can you help me, I do not understand the following:
3rd Row K1, sl1, K1, psso, work in part to last 3sts K2tog, K1
4th Row P2, work to last 2sts P2. Rept the last rows until 85 sets remain.
Next row K1, sl1, K2tog, psso work to last 4sts K3tog K1.
Work 4th 3rd and 4th rows again.
Rept the last 4 rows until 37sts remain finishing on the Dec row.
There is no mention of rows 1 or 2?
This is the decreasing on raglan armholes. Thank you.

I thought I knew but that would be for in-the-round and based on your instructions, you’re working flat? So this is a body piece you’ll eventually sew to the other parts?

It mentions pattern stitch - so it’s not straight stockinette? Is the pattern stitch a four-row repeat? In which case, rows 3 and 4 here (with the decreases) are replacing the regular rows 3 and 4 in the pattern stitch. So row 1 and 2 are whatever you were working before as rows 1 and 2. (In which case, it should have told you to stop at row 2 before starting the decreases.)

Would need to see the pattern or the instructions directly before to answer better. Link?

I agree that a pattern link would help or even a pattern name.
Essentially, it sounds like, after you get to 85sts the repeat is:
[B]row 1:[/B] (former Next row) K1, sl1, K2tog, psso work to last 4sts K3tog K1.
[B]row 2:[/B] (former 4th Row) P2, work to last 2sts P2. Rept the last rows until 85 sets remain.
[B]row 3:[/B] (former 3rd Row) K1, sl1, K1, psso, work in part to last 3sts K2tog, K1
[B]row 4:[/B] (former 4th Row) P2, work to last 2sts P2. Rept the last rows until 85 sets remain.

So you’re alternating a 4 stitch decrease row (row 1) with a 2 stitch decrease row (row 3).