In Step 51 you were asked to press the hem up 2". Now is the best time to put a finish on the raw edge of the hem. There are many ways this can be accomplished. If you have a serger, serge the raw edge. If your fabric is prone to fraying, you may want to turn under 1/4" (wrong sides together). If the fabric is bulky and you don't have a serger, zig zag the hem edge. If you need more help, please see Basic Seam Finishes.

Step 54 asks you to turn the band right sides out and press. When you are pressing, be sure to line up the raw edges and press the band perfectly in half lengthwise. Make sure you line up the center seam.

Step 55, asks you to unfold the hem on the garment that you previously pressed in step 51. You do not want to press the crease out.
"Place the Band on the garment Fronts matching cut edges and with the stitched end of the band at folded edge of hem. Pin in place."
To translate: Take the long edge of the band and place it along the front raw edge of the robe front pieces. Line the ends of the band that you preciously seamed, along the fold you made for the hem and pin the band to the robe front to hold it in place.

Step 57 tells you, "Stitch Band to garment, beginning at lower edge and stitching to center back neck on each side" In other words, start at the hem area, with the band on top and the robe front at the feed dog of your sewing machine. Stitch the band on until you reach the center back where the seam of the band is located. Stop there and start sewing on the other front band following the same procedure. By having the robe front facing the feed dog it will help feed in or ease in any possible excess fabric.
Apply a seam finish to the seam allowance that joined the band and robe.

Step 58 Tells you to turn the band to the finished position and press the seam allowance towards the garment. While you are pressing, be sure to press the seam out as much as it will go. Use the tip of the iron into the seam to press the seam allowance in the direction of the body of the robe. In turning the band you will need to return the hem to it's proper position also.

Although the directions do not call for it, you may want to top stitch the seam allowance to the robe. You see it done that way on many ready made garments and it works well to keep the seam allowance where you want it to stay, especially on a garment that will be laundered regularly. After pressing the seam allowance, from the right side of the garment, on the body of the garment, use your pressure foot as a guide, along the seam, to keep your stitches an even distance from the seam, while stitching on top of the seam allowance.
Most newer machines have a stretch stitch (represented by 3 lines of stitching next to each other). I love using this stitch for a nice heavy decorative top stitch.