You cannot hook up a DSL line directly to your switch and share the internet.
Hooking the DSL line directly to your computer and using it as a server for the other computers = hard to setup. It requires some additional software and I can't which software that is, because te way I have every successfully got that to work is use Windows Server Software.
Has anyone else had success at do this without the use of Server software?
OK...answer #3...the one you want.
Buy a router. They are cheap, effective and VERY easy to setup for all three computer to use the same internet connection.
I recommend a wireless router with a built in switch. Like...
But if the computers are that close then a non-wireless router will do. Cost for either is about $60.
Don't get just a router, because you will only regret it later. It takes up space, extra cables and power outlets, as well as, extra power.