Need some advice

Ok so here is what I have, I have a small office medical office with 4 desktop computers and 1 computer that is going to be designated as a server. I need to run an medical billing software from the server to all 4 desktops, I have Windows Server 2008R2, but I am not sure what is the best way to configure the server or the desktops. These desktops also must have intrenet access as well. Any advice would be great.