Take your Ziploc bag and line the bottom of the bag up with the rings of your binder. As you can see, the top of the bag sticks out past the binder's cover! By folding the bottom of the bag up onto itself, shorten the bag to your desired length.

With your bag folded, secure the folded flap with a strip of duct tape. The tape should be slightly longer than the bag, so that there's a little bit overhanging on the sides.

Continue covering the bag with strips of duct tape. All your strips should hang over the three sides of the bag (left, right, and bottom). Do not tape up the top of your bag! You still need to get in and out of your pouch!

Flip your bag over and fold over the overhanging tape.

In this picture, the bottom strip of tape has created two "tabs" on the sides. Very carefully trim those tabs away, being careful not to cut the bag itself.

Cover the other side of the bag with duct tape. Fold over any overhanging edges.

Once again line the bottom of the bag up to the binder's rings. Using a marker, make a dot where each ring is.

Use your hole punch to punch holes at each mark. (You might need an adult to help; it's hard to get the punch through all the layers!)

Continue decorating your bag with more duct tape, stickers, markers -- whatever you like!

Now your can put your pouch into the binder's rings, put some pens and pencils inside, and seal it up nice and neat!