help needed with armhole pattern!!

[CarlaElena]

hello. i am knitting a sleeveless blouse, and am just coming to the part where i need to "shape armholes". however, i am a bit confused with the instructions. here they are:

Shape armholes
Cast off 4 sts at beg of next 2 rows.
58 sts.

Row 1 (RS)
K2, K2tog, K to last 4 sts, K2tog tbl, K1, pick up loop lying between needles and place look on right needle (this loop does NOT count as a st), sl last st purlwise.

the pattern continues with instructions for Rows 2 through 4.

-my question is, for the 'shape armholes' part, do i cast off 4 and then knit or purl all the way to the end of the row??
-also, it doesn't say this, but should i also cast off 4 sts at the end of those two rows??
-OR, do i cast-off 4 stiches then start with Row 1 straight away?

i feel like something is missing here, or i just don't get it at all...

someone please enlighten me...

thanks for the help,
c.

[Jints]

You can only cast off sts at the beginning of a row. so you need to:-
Cast off 4 sts beg of row, work to end, turn
Cast off 4 sts at beg of that row work to end.
(The one row difference in the armhole levels are not significant)

[CarlaElena]

thank you Jints...that makes sense about the casting-off.. :)