I need help...once again

I am still working on this pattern

and this part “[B]Beg with a WS row, work 5 rows in St st, then cast on 30 (32, 34) sts above bound-off armhole edge [/B]” has me completely confused…somebody please help me!

You are creating a slit in the fabric for the armholes. See the diagram on pattern.
[I][COLOR=indigo]Beg with a WS row,[/COLOR][/I]
Start with the Purl side facing you
[I][COLOR=indigo]work 5 rows in St st,[/COLOR][/I]
[I][COLOR=black]p, k, p, k, p,[/COLOR][/I]
[COLOR=indigo]then cast on 30 (32, 34) sts above bound-off armhole edge[/COLOR]
Knit K 52 (54, 56), cast on 30 (32, 34) sts, to fill the gap in the row where you cast off before. (Use Cable Cast On, or Single Cast on) and knit the 30 sts from previous section, to rejoin the other part of the row.

You would use a knitted or cable caston.