Resources for designing 4 layer PCBs
Four-layer design with power and ground planes is refreshingly easy compared to two-layer!  You'll want to familiarize yourself with the stackup editor in your tool, first off -- as to layer stackup selection, the "canonical", if nothing else because it's the simplest to lay out, stackup for a four layer board is signal - power - ground - signal, assuming your board runs at a single voltage.

When laying out, the signal traces stick to the two signal layers, and power and ground are accessed simply by dropping vias down where appropriate instead of having to run traces for them -- the lack of traces for power and ground running all over the board makes routing far easier.  (Even though it's not great for signal integrity, even the most basic of four-layer stackups is still much better than a two-layer board.)