Visit the Comcast Central homepage and find the "Welcome" Box. In the "Welcome" box, below the content, find a link labeled "Register for access." Click on that link to bring up the registration pages.
Provide your Comcast account number and your telephone number as requested on the registration page. Click on the "Next" button to continue. Complete the registration page by creating a Comcast ID and password.
Check your email for a confirmation from Comcast. Click on the link in the email provided to confirm your Comcast registration. Upon clicking the link, you will not only confirm but also log into the Comcast Central site. Once you gain access, you may then review your account information and make changes when you need to.