What a great way to pretty up a window!
I scored on this too. I got that 60 piece non-breakable ornament set for $8. It was 50% off, sweet! I also got my ribbon for 50% off...paying a little over $1 for each roll.
You will need your ornaments of choice, ribbon, hot glue gun, scissors, and safety pins (optional).
Take your ribbon and thread it thru the top of your ornament, making a loop and securing the end with hot glue. This way you have no ugly knot and everything looks smooth and seamless. Hanging will depend on how you wish to do it. You could just tack the ribbon to the wall above window. You could also put up those little removable hooks on the wall to use. I hung mine right from the curtain rod. But I wanted to make sure I could easily remove it without having to untie any type of knots. So I simply looped the ribbon around the curtain rod and secured with a safety pin! Super easy and super pretty!