Anki is a memorization application.
It has decks: which has a bunch of cards, each card is something you will force into your memory.
It'll give you a word/letter/sentence, and you'll think for yourself what it is.
You probably won't know if it's the first time, you'll click "show answer" and it'll show you.
Then you select one of the options based on how you fare your knowledge of that card:
Again, Hard, Good, Easy
Anki will manage when it'll show that card again for you based on your answers. You can see above the buttons when it will show next as your "daily exercise".
The more and more you get it "right", that is, you click anything that's not "Again", it'll show even less and less since you supposedly know that already.
Whew, that said, that Anki seems broken or badly configured, like other anons said, the font, and with that I can't help.
I'd recommend AnkiDroid (or it's iOS version) though, you can bring it anywhere since the point is doing the exercise everyday, without fail, until your brain gets hammered with the information.
It's also good for doing it while shiting or in the bed before sleeping.