Playing ZooDangle is super easy
The Main screen looks like this:
The word you're trying to solve is in the box labeled "The Word". Simply start typing letters, to guess. As you type your guesses, they will either populate "The Word" box, or earn you an appendage on the gallos to the right. If you type the same letter twice, ZooDangle will ignore you. All of your guesses wind up in the letter box, so you can see what you've already guessed. Keep guessing until you either earn all 6 appendages (head, torso, right arm, left arm, right leg, left leg) and lose, or successfully solve the word. If you win, the character drops off the gallos and is happy, otherwise it just sort of hangs out being disappointed with you until you start a new game.
ZooDangle has three difficulty settings. They can be accessed with the 'Menu' button. On Easy mode, you get two bad guesses before you earn an appendage. On Normal mode you only get one guess. In Hard mode, you only get one guess, and the words are from your SAT Nightmares.