hi tonlee! REMEMBER: only main. NO contrib and ABSOLUTELY NOT non-free.
This page will help you understand how to set your sources.list properly -> https://wiki.debian.org/SourcesList
I can already tell you to set it like this (no need for backports unless you want to mix stable components of Debian with components from Debian Testing, although adjusted and recompiled, which can lead to a non-stable system, that is crashes and general headaches). Read about backports here: http://backports.debian.org/
deb http://ftp.us.debian.org/debian/ jessie main deb-src http://ftp.us.debian.org/debian/ jessie main deb http://security.debian.org/ jessie/updates main deb-src http://security.debian.org/ jessie/updates main deb http://ftp.us.debian.org/debian/ jessie-updates main deb-src http://ftp.us.debian.org/debian/ jessie-updates main This is all you need in your sources.list cheers!
