Apple Mail, Outlook and Comcast mail

Just set up a new imac and can not get my Comcast mail.

Previously I was using a PC along with Microsoft Outlook to get my mail.

Was able to set up Comcast mail on my iMac, but am not receiving mail. I can send email fine.

When I log into Comcast my mailbox is empty. I think it goes directly to Outlook somehow.

I don't want to use Outlook any longer, I want to use Apple Mail.

Ideas??