How to download source.list for ubuntu
 

Pardon my ignorance, but how do I download source.list for Ubuntu? I need to download it to use it elsewhere
The instructions are as follows:
When I go to the "here" link I get this:
Does anyone understand what this means? What the heck am I supposed to do?

it is the content of the sources.list file i guess

Just copy it to /etc/apt/sources.list,lets say this is the file,I'm going to copy and paste it,or like they suggest use the command line because they use sudo for some reason,you must be root;
just add that to the file anyway you can as root.Also you may want to put a ## in front of the universe and multiverse until you know what you are doing,on some distro's installing straight debian will break them because they are a mix of unstable and testing and sometimes experimental

How do I uncomment?

u could simply open synaptic and in tools -> repositories

just check all the list then press reload

its the same thing as synaptic will uncomment them

Thank you much