When you register on Cardzilla, you must enter your email address. It is very important to use a real address that you can access. Right after registration, Cardzilla sends an email with a special link. To confirm that the address exists and that you own it, all you need to do is click that link.
If the email does not arrive, check your spam folder in case it ended up there by mistake. You can also go to your profile and use the button to resend the confirmation email.
If you entered the wrong email during registration, you can change it in your profile. You can do this several times as long as your email is not yet confirmed. Each time you enter a new address, a new confirmation email will be sent there automatically.
Confirming your email is very important. Many features of the site are not available until your email is verified. Accounts with unconfirmed emails are also deleted after some time, so it is best not to delay the confirmation.