Welcome to a two year course. Yeah, you want to learn it all now, but you can't. Why? Well, we don't know everything. What we think are truths are really just approximations. And we don't even know all of the truths, not by a long shot.
How do you find these near-truths? Experiment. The results of an experiment are wrong only in that they are inaccurate. If they don't follow your "truth" (your theory or hypothesis), then your "truth" isn't. It's actually wrong, so adjust the hypothesis and try again.