well I'm a little late to this party :3
Building computers:ChooseMyPC.net as you may or may not know only certain groups of computer parts will be compatible with one another and this will give you a starting point with a preset configuration. From a starting prefabricated build point you can search the tools you need and get a grasp of why parts are compatible and how they fit together.
Programming:There is usually a small debate as to whether someone should start to learn C & C++ before they learn Java. Though if you're not the type to handle a giant explosion of information all at once I'd honestly just start with Java by itself and move up from there (which is how it works at the college I'm attending)
Networking:I mean anyone can pretty much set up their own router / home network, but to get into managing / fixing networks you'll have to look this one up as that's as far as my knowledge goes.
hope I helped you nitpick some topics
if you have any questions I at least have some decent knowledge on the first two as I've built a few project computers and studied some java myself.