As the Freakonizer combines the upper and lower part of 2 faces, you need to take 2 pictures of two different faces. When you take the first picture, that will be used as the upper part, you can see directly what portion of the face will be used.
Next you'll need to take another picture. With the help of a semi-transparent overlay you can adjust the first picture on the other person's face. Now only the lower part of the picture will be used. Did we mention that you don't necessarily need to take a picture of a person? You might also want to try with your cat or dog.
After you've done all the hard work, you can save your freak to your phone's photo album or even share it on Facebook.
If you experience any problems please visit the support page.