When your Registration was completed, a password was sent to you by email. You can customize your password very easily. After logging into the site using the Username you selected and the password emailed to you, click on "My Account" from the personalized options at the bottom left of your screen.
Click on the "Edit" tab at the top.
You will see your Username and email address filled in, with space for "Password" and "Confirm Password". Following the instructions, enter your new password into both spaces.
Click on "Submit" at the very bottom of the page - and you now have a new customized password. Use this same process to update your email address if it changes.