Start by planning out your design. You will need foam for the back and front of the headband. Cut them out opposite to each other. If you don't like to get glitter in your hair, then you might want to cut out normal foam for the back that lays against your head. But who the heck doesn't like glitter in their hair?
Then peel off the backing from the front and back pieces. Carefully stick them together over the headband. The backings of the glitter foam really sticks to itself, so be careful. Trim wherever there is sticky showing or you'll have some hair pulling when you try to wear it.
Next, peel all the rest of the decorations and stick them on the headband where you want them. Use a little hot glue to stick them down after you have them the way you want. You really don't need to glue them down because it should stick well enough, but I found with multiple hair and headband adjustments, the letter might get loose. They don't stick as well to the glitter side of the foam as they do to the back.
Make more with other exclamations on them!
And even more!