Super simple to use, all you need is some tin foil/aluminum foil some tape and this model. 

Just cut a small square of foil and tape it to the top of this eclipse viewer.

Then poke a small hole with a needle in the middle of the foil. 

Finally just bring it outside and shine it in the sun at the right angle and a small dot will appear in the viewing hole.

Note: I didn't have enough time to print out the tall one, but the tall one should create a bigger image in the viewing hole.

The hold you poke on the foil should be barely visible as shown in this photo

Quick Diagram: