Step 10: Stitch the band to the crown
First, pin the crown to the band, outsides togehter. Ease or stretch a bit if they don't exactly match. It's fine if they're off a bit, I don't worry unless the band is bigger by more than about half an inch, or the crown is bigger by more than about an inch and a half. Just make sure the bigness is spread out evenly. Consider the placement of the pocket with reference to the brim, if you added a pocket.
Sew this seam together along the stitching line you just did.
Next, bind the raw edges using one last piece of quilt binding. The technique is very similar, start with an unfolded edge and fold the end down a quarter inch. Stitch all the way around over the fold, which should be on top of the old stitching line.
Now fold the loose piece of quilt binding over the raw edges and down to the inside of the hat. Make sure the other pre-folded fold is folded (how's that for clarity!). Pin if you are more comfortable with that, or just sew "in the ditch" of your last seam, making sure to catch in the folded edge underneath. This is called binding an edge, and it's hard to describe, so take a look at the pictures.