Open some of Epic's material shaders and break them down, it may look complicated (wires/ nodes everywhere) and un-commented but break them down (disconnect nodes, preview the nodes (right click on a node > Start Previewing), change the properties of the nodes...etc) There's also this video on how to create/ setup a master…
Most of it, yes. Math is math and most nodes remained the same really. Most if not all UDK material tutorials can still be followed in UE4 and get very similar results, so if you're finding yourself scarce with tutorials or documentation (which I doubt, there's a lot of stuff out there already) don't be afraid to check…