There’s not much to the process compared to a standard Diffuse/Specular/Gloss/Normal workflow, for which there are lots of well established tutorial series. The only difference is what maps you put detail into.
A good starting point is either D1ver’s material library (Moose linked to it in his post), or grab the trial of Quixel’s dDo which is probably the best way for anyone to learn PBR. Even if you insist on creating stuff from scratch after using dDo, it’s a great learning tool.