Leave the ribbon on the spool and cut it once the bow is finished to save on wasting any ribbon.
Make a loop making sure the cut end, which will be one tail, is on the top and pinch to hold.
Wrap the ribbon around the front to form a small loop and bring it around to the back. See how the underside of the ribbon is now showing? Give the ribbon a tight half-twist close to where you are pinching the centre, so the printed side is uppermost and push it through the central loop as shown below to form the bow.
Gently pull on both loop ends to tighten the centre knot. You can make adjustments here to ensure your bow is the size you want and that both tails are sitting flat.
Once you are satisfied, pull tight and trim the ends.
Do check out my Fork Bow and Potato Masher bow too. All these bows are excellent for attaching to your card making or scrapbooking projects.