I am knitting the seascape bolero from "The Knitter's Book of Yarn." I have just finished my first sleeve and am at the point where I need to add stitches for the body. The pattern states to cast on a number of stitches at the beginning of a RS row, work the existing stitches, and then cast on a number of stitches at the end. I know how to do it at the end, but how do I cast on at the *beginning* of the row? I just can't wrap my mind around it. Any help would be much appreciated!