After you hit <go> you do not need to do anything after - you are already signed up at that time and can close the new window that was created.
Most browsers will reply with a thank you page after you hit go, but a small number may return an error. If you get an error you are almost for sure really signed up, check for a confirming e-mail (there is some chance you provided an invalid e-mail address of course so the error may be real) before trying again.
Note that the spam filtering software used by most of the browser based email providers (like Hotmail and Yahoo - other may be affected also) will often decide to block there messages as they go to multiple people. If possible do not signup with a Hotmail or Yahoo address.