How to:
First box, choose the data you want to be tested on (verbs, adjectives, etc). Choose whether to translate from English to Spanish or vice versa. Select the chapter you want to study. Click the button that says "Drill ###". Then, you will see a word. Guess what the word means. Click show. If you got it right, click "right", if you got it wrong click "wrong". If you do the latter, you will be tested on it again, otherwise you will not be. Enjoy!
All words tested are printed on the testing page. You can use these to make your own physical cards if you prefer. Copy them into word and replace the "_" with a few tabs. Print them, fold the paper in half, and hey presto: flashcards!
Also, you can change the font size: click on the F, O, N, or T in the top left corner of the page. N is default. Click on "night" or "day" to change things up.