Although I've never heard it called "rotating" before, it is different from turning your work. Basically, once you "knit 1 more row, do not turn," you will "rotate" your knitting 90 degrees so that the side of your work is now the "top". Your working yarn should now be in the correct position to pick up the new stitches. Then rotate 90 more degrees, so that your cast on edge is on top, pick up those stitches, and rotate 90 more degrees and pick up the last set of stitches. You will always have the same garter stitch rows facing you (i.e., you won't be switching from the front or back of the piece).