Umm, pretty simple, eh?
Open putty and establish your connection to the VPS.
You gotta use a text editor such as nano to edit sources.list. Run this command:
sudo nano /etc/apt/sources.list
Then navigate to the end the file (a new line maybe) and keep Putty window open of course.
Simply copy the repository addresses you want to add to sources.list file to your clipboard.
Then right-click inside the Putty window and repository addresses will be added to the end of the file (if that didn't happen you can write the addresses by hand).
Press CTRL+O
and then Enter
to save the file.
That should be it.
vim
,emacs
or install another text editor. – Hossein Jafari Mar 09 '15 at 08:19