Take a piece of yarn or string and measure from your underarm, up and over your shoulder, and up under your arm. Don’t make this tight; to be safe, I always add 6 inches to whatever length I have measured. Measure out a piece of tape the length of your string. I like to lay my tape sticky side down on my work surface then carefully pick it up and flip it over, sticky side up. This removes some of the stickiness, which is helpful in the next step.

You may want to grab some extra hands to help you with this step if you are making long straps. With the sticky side up, fold the tape onto itself a third of the way.

Fold the remaining sticky tape down over the folded tape. All of the sticky side should now be folded away inside. Make two straps in this manner. If you are making a larger backpack, you may want to simply fold your strip in half instead of thirds.

Take one strap and insert it into the top slit in the back of the bag, feed it through the inside of the backpack, and out the bottom slit. Repeat this process on the second side.

Repeat this process on the second side.

Take two key rings. Lay them on top of each other. Slip one end of the strap through the two key rings, and pull about 3 inches through.

Secure with a strip of tape. Wrap this around the strap so that it’s super strong. Repeat on the second side.

Trim the strap ends so that they are nice and rounded.

To secure the strap, slip the loose end of the strap through both rings...

... and then feed back through the top ring.

This will secure the strap, but also allow for adjustments.

Now your straps are done -- onto the fastener!