After you have registered for the web site, you will receive an email with your username and password to access the member area.  If you cannot login and you do not have that email, choose forgot password, enter your username (the email address you used to register the site) and click "forgot password".    The web site will send you another email with the login credentials in it.  Check your junk email filter as they could show up there.

 

You can change your password by logging into the website and clicking "your profile" at the top left of the page.  Change your password there and make sure you scroll down and press submit for you changes to be made.