I just installed UCS for the first time with no linux background. All I need is to work with proxy server/squid bu I know how to setup and configure the server. The server is already installed but I don’t know to configure it. I tried to follow the documentation but can’t get it.
In the document it says: open the file /etc/squid3/local.conf. My question is how to open this file?
In general it is easier for us to answer your question if you could provide informations which documentation you are referring to. A link would do.
How would you open a file on other platforms? I guess that you want to change things in the file, so you need an editor. There are command-line editors like joe, vi (where you have to figure out how they are working), file-managers like mc (Midnight Commander, a clone of the old-school Norton Commander). If you are working on Windows you could try a tool like WinSCP which may have the ability to edit a file.
I would recommend to search for a “beginners guide to Linux” and would expect that you find a lot of useful information on the net which does not necessarily to be repeated here.