I agree with Yvonne. A search for steeks might help you find pictures and more specific instructions. I don't think this is technically a steek, but the technique is similar.
It sounds like you'll be knitting two extra stitches for the center of the cardigan. When you've done the front, you actually run the sweater through a sewing machine (set on a small, straight stitch). I believe you'd sew in the middle of those two stitches (sewing two lines), and then cut the knitting right down the middle, between the two stitches. Then you pick up stitches on both sides, and knit a nice border.
I've never done this technique, because I like my sweaters to be unravel-able. But this is my understanding of it!
Happy knitting to you and your friend!