Some people have been confused by the mechanism here. Assume that your answer to puzzle 4 was "AARON". It's not even close, but let's pretend. So you'd write "AARON" in the five boxes under number 4. Since "AARON" would be the first answer alphabetically, you'd apply the first mask in the list on the right, which has four open squares and one black square, so you'd blacken in the N at the end of AARON and you'd be left with AARO. Once you've done that to all eight answers, the letters that you haven't obscured can be read to form the answer. I've even given you an apostrophe where needed!
The "masks" taken in order from top to bottom correspond to the answers to:
6 5 7 3 8 2 1 4