It is by no means the answer to all of your problems, but as a starting point, I'd suggest using the search feature here to find the thread "Let's go to the Library" (I think that is the name... searching just for Library may find it). It gives a detailed breakdown of a sample hack (with a decker and a technomancer competing). Read the discussion afterwards too, to see how confused most people are, but also for additional insight.
Also let me (probably mis)quote a signature that I saw someone using on one of the SR boards: "The more the GM understands magic, the more powerful it is. The more the GM understands the matrix, the less powerful it is." It turns out that the matrix in SR5 is pretty good -- still hackable, but it isn't as easy as the fluff in the books makes it sound.