How to install ports from CD-ROM

[耗 子]

Hi.every one.
When I was installing Freebsd 5.3, I found it downloaded ports from
the internet although I select CD-ROM as my install media.How to stop
that? Since I did not use a high-speed internet connect, it cost me a
lot of time.
BTW: Could someone tell me how to change the site from which FreeBSD
ports to download the source cod.
Because  English is not my native language, maybe there is some
mistakes in my letter. I have to sorry for my bad english.
Thank you.