Unable to point my domain from domain.com to my site here

For starters, I would suggest to check this article. It describes how to add a domain name to your account:

If you get stuck trying to follow this guide, please clearly say where in the process you’re having trouble, and what you see there. Especially any error messages are really useful for us to understand what’s going on.

Finally, it would help a lot if you could share the domain name you’re trying to setup. It’s very hard for us to check why you’re unable to setup a specific domain name without knowing the domain name.