The word is hidden, all but three letters. You can see how long it is and where those three sit.
OUN
Guess the box right next to them. Tap the glowing box on the left or the right, pick a letter, then press ✓.
Right, and a ghost carries the letter in. Wrong, and one of your five ghosts flies off.
Yellow means that letter is in another empty box. Grey means it isn't in any of them.
Know it? Guess the whole word. Get it right and you're done. Finish with as many ghosts as you can.
Solved
Each ghost wears something that starts with its letter