Just sign in, click on your name (see the top right of the typing area that says Welcome, Jhorne89 - click on your name here). It goes to your personal page. Then click on the "settings" link in the blue box on the top. Then click on the link on the left link that says "edit signature". It should open a new page that has a text box where you can type in your signature.
Last edited by J-Lu; Jan. 2, 2013 at 12:06 AM.
Reason: I got it wrong at first!