I am new to both linux and unix. I just installed Gnome to the hard drive on a very old laptop. According to the documentation on this website, "To install Gnome, you have to comment all the lines in /etc/apt/sources.list except the unstable ones." This must happen before typing:
apt-get update
apt-get install gnome

Is there anyone who knows how to do the first step (commenting /etc/apt/sources.list)? I think I generally understand how the apt-get function works, but why do I need to comment all the lines in /etc/apt/sources.list?