Hi - this may be moot if you've moved on to another pattern, but I think you're talking about a pattern from Melanie Falick's Weekend Knitting
book? I've used that pattern, and if I remember right (I'm not at home and don't have it in front of me), it's knit side-to-side, not top to bottom like most sweaters. Each row of knitting runs from the bottom of the sweater to the neck. If you start or end the row on the shorter needles, you get a smaller rolled cuff along the bottom of the sweater. The cuff is in stockinette and the body of the sweater in garter stitch, I think. I used straight needles for the body and a smaller double-pointed needle for the cuff. It's not too hard - you just knit the first few stitches with one size needle, then switch to another. The smaller needle just kind of hangs out with a few stitches on it until you get back to it. But there are lots of other cute baby sweater patterns out there, so I say don't sweat it if this one seems like a pain.
Let us know how the sweater turns out!