[Centos] Newbie Questions - Yum, etc.

Hi All: My name is Peter J. Mignone and I have a little Linux experience. From what I have read about CentOS, it appears very interesting so I am trying it out. I get a header.info error when I tried yum which I have never used. How do you set up yum? Where do you point it, etc.?

If my understanding is correct about the licensing, I should turn off anything pertaining to the Red Hat Network. Is there anything else that should be removed?

Is there any restrictions on rpm for Red Hat enterprise. In other words, If I find a rpm on say rpmfind.net for red hat could it be used?

Thank You!

-- Pete