Ask HN: New to HN's and have some questions

First is there a FAQ somewhere?

This may be answered in such a FAQ; if so I apologize in advance.

I've been a member of this fine community now for a couple of weeks. In my reading of comments I've noticed some remarks talking about down voting. How does one do this? I only see an up-vote arrow, nothing seems obvious to me on how to down-vote an article, that doesn't seem to mesh with Hackers News culture.

Thanks. Stephen Toronto