2 Answers

How what works?

If you are talking about THIS, you've already figured out how to ASK a question.

To ANSWER a question, place your cursor in the "Add new answer" box and start  typing.  Click on "POST AN ANSWER" when you're done. 

If you like an answer (or question) that someone else posts, click on the brown colored thumb up icon.  If you don't like something, leave it alone. The thumb down is just for show. 

There are categories of questions, which you can find by clicking on the word "Categories" up at the top of the page.  

Mostly, just putting your cursor where you want and clicking will take you from question to answer, etc. 

Remember, stay away from the thumb down icon.   If you want the "formal" rules, go to the bottom of this page, and click on "akaQA rules"