Create more score lines as indicated by the black dashed lines.
Mountain fold all the black dashed lines and valley fold the solid red lines. Remember to punch your decorative edge on the flap!
Add some form of closure. Here I've used a little piece of hook and loop fastener but you could also use magnetic snaps. When pushing them in together try to stagger the long flaps on either side and just take care that they don't get caught on the wrong side of the short centre flaps or it will be practically impossible to close. You'll know something is wrong if it doesn't want to push together reasonably easily.
I hope this makes sense. If you get stuck let me know and I will try to explain more clearly. All that remains is to add a piece of 5mm ribbon as a handle if you wish (I usually put it in the 1/2cm gap at the top) decorate the inside and embellish the outside of your little bag.