Although many find the around-the-head elastic to be more comfortable than ear loops, you may find that ear loops are necessary in certain circumstances, or you may prefer them. Here's how to convert the elastic into ear loops. (If you ordered before I had the cord stoppers in stock, you can also just cut the elastic in half at the loop and tie a knot on each side where it's most comfortable for you; it simply won't be adjustable.)
You'll begin with the elastic threaded as you received the mask, with the elastic looped at the bottom of the mask. (If the elastic has come unthreaded while you practice with it, use the included safety pin to rethread it.)
Make sure there's an equal amount of elastic on both sides of the loop, and cut the elastic in half.
Thread the cut elastic ends of one side of the elastic onto the included bobby pin. It's pretty tricky to thread both at once (it required a great deal of tugging for me), so you may wish to do them one at a time, but I photographed the series with both at once.
Thread the elastic through the included silicone cord stopper.
Tie a knot in the elastic ends so that the cord stopper is between the mask casing and the knot. This will keep the cord stopper from getting lost. If the elastic is too long, you may want to cut some off and then tie closer to the mask; just don't cut off too much, or the loops will be too tight.
The mask will fit better if there is some gathering on the sides,so don't be worried if it pulls into gathers when you wear it. You may want to rotate the elastic so that the cord stopper is below your ear instead of behind it -- wherever it's most comfortable for you.
Now you're ready to wear the mask! Go out and be safe.