For each word in the list on the left side: click and hold on the box beside it and choose its antonym in the list that pops up. When you're done, click on "Check Answers." If you don't get them all right, get out the dictionary, figure out the right answers, and take the test again until you get them correct. Then, most importantly, follow the recommendations in the section on Vocabulary Building to make these words part of your own vocabulary.
The name Auntie Nym is a registered "character" of Vocabulary University and is used here with the gracious permission of Sam Mantics Enterprises and Carey and Jan Cook, creators of Vocabulary University.