If you've never worked on cars at all, start small, proper tools, read up, if you have low mechanical intelligence (which doesn't mean you're stupid in a general sense, it's just that some people can't grasp the mechanical), forget it and pay the tax (mechanic)—it will be cheaper. This is why beaters are great—you can mess with them cheaply, parts are in the junk yard, and they're ideally something simple and robust, so they're hard to screw up too badly. If you can find a junk engine and a place with a stand, you can learn a lot from tearing it down. If it's a cheap engine that's not too much junk (economically rebuildable), getting it running again will have you feeling through the roof.