i need help with knitting phrase
ok, am knitting a vest for the first time and now am stuck when it got to the part of shoulder shaping,
i cant seem to understand the instructions below, i dont know if am suppose to cast off on both sides or just one side since am shaping the back.can anyone help me please.
Shape shoulders: Cast off 8 (10-13-16-19) sts beg next 4 rows. Leave rem 31 (37-39-41-43) sts on a st holder.
Shape shoulder: Cast off 8 (10-13-16-19) sts beg next and following alt row. Leave rem 16 (16-18-18-20) sts on a st holder.**