Not a ridiculous question! We've all been new to this at some point
As for your FTP credentials, you can refer to the email we sent you when you first set up your FTP. There, you'll find your username and FTP server. If you forgot your password, you can just head on over to your DreamHost panel, and under "Manage Users", click "Edit" to the right of your user and change your password. It takes 5-10 minutes to take effect, but after that you should be able to log in!
If you find yourself needing help, please don't hesitate to email our awesome support team, we'll be happy to help: http://bit.ly/SlXpjh