Starting out with node.js and sockets for live web interaction [on hold]

I am new here and very new to node.js and sockets. Basically I have a website that is pretty static and I would like do the following and would like to know where the best resources or examples are to start and what I would need to proceed. I have web hosting that has node but I have to install it which I am not sure of how to do this or do not understand the JSON installer packages instructions etc.

I would like it when a user logs in somewhere there is a live connection made. When another user signs in they can send a message or something and then it alerts the other user that they have a message but in real time. The alert could be on a navbar or a pop it really is not important, I just want to get the feel of how it works and the correct way to proceed with more complication applications.

I am not asking for code just where to start as all the examples I have found are like chat programs that seem to run on a local server which I have not got setup but I would like it on my server and not really sure how to install from scratch.

Any help would be greatly appreciated.

Many thanks

Lucy