I know that probably sounds like a silly question, and yes...I did read the manually...
Unfortunately, there is nothing on my screen that says "Account Settings". There is a menu item "Settings and People", but there's nothing there about API keys.
Hello! From your description, it looks as though you might not quite have admin access to your account, or you might be logged in as a client. If you're logged in as a client, I'm afraid that the 'Account Settings' link would not show up for you.
If you do have administrator access, I would go ahead and log off, and try to log back in using the email address you used to set up your account. If you're still having problems, feel free to email into support (firstname.lastname@example.org), and we'd be happy to help investigate a bit more for you. :)