Trouble reading pattern

[Linster]

I've come to a part in a pattern I'm working on (front section of baby sweater) where it reads:

You will now have 21 sts on the needle. Place a marker thread at neck edge. Work 19 rows dec 1 st at neck edge in 3rd and every following 4th row.

Do I decrease at the beginning, middle or end of the decreasing rows? It doesn't specify and I'm too much of a newbie to naturally determine which would be correct.

[cam90066]

As pattern says, you'll only be dec at the neck edge (where you positioned the marker). For instance, if the left front section, you'd work from the armhole edge to the neck edge, do your dec. Then do the WS, RS, etc w/o decs. Only do the decs on the marked edge on the appropriate rows.

cam

[Linster]

Ahh. Great. thanks for the help.