Need Help Interpreting Pattern

Pattern says:

Shaping Sleeves: (bold)

Cast off 3 sts. at beg. of next 2 rows. Work 2 rows straight.

1st row(bold): k.2, k.2tog., K to last 4 sts., sl. 1, k.1, p.s.s.o., k.2
2nd row (bold): purl.
Work 2 rows straight.

Question: Is the first instruction regarding ‘casting off 3 sts’ a summary of what is coming, whereby you follow the instruction for ‘1st row’ then 2nd row?
OR, are you supposed to cast off 3 sts and then proceed with the instruction for ‘1st row’? If the second scenario is the case, what do they mean by ‘cast off’?

None of it really makes sense, because if I assume the first instruction is a summary of what’s to come, by following the instruction for 1st row and 2nd row, you only eliminate 2 stitches in the knitting row and none in the purl row.

Any help would be greatly appreciated. Thanks!

First you cast off three stitches at the beginning of the next two rows. Casting off is the same as binding off. This is an instruction rather than a summary of things to come. They don’t really name the rows since it’s a one-shot deal.

Then they give you directions for row 1 and 2. You work those next, work 2 rows straight, and I suspect that you’re told to repeat these 4 rows over and over, or something similar.

Ah ha! I had no idea that cast off meant bind off. Now I can proceed! Thanks for all your help!