The interface is designed so that you can do everything with a controller, though some things are understandably more cumbersome. Like Ogulbuk suggests, a keyboard is pretty much a no-brainer for an MMO, to properly communicate if nothing else, (though I suppose you could be using Teamspeak or similar). Even if you're planning to use the controller for most things, a mouse is super helpful here and there. From what I understand, as far as control options are concerned there should be very little difference form PC and PS4, and on PC I actually use a PS4 controller, KB, and mouse. The mouse is mostly for the things you described -- setting/ moving skills on hotbar, as well as universal things that i don't put on the X-hotbars (mounts and gearset icons for job changes mostly) but instead put on shared hotbars on the sides of the screen.

If you just want to use the controller then ZhaneX has you covered. Since you switched platforms you must have already passed all the little tutorial pop-up things that show up anytime you do something for the first time. I forget where you access those things again, but many of those cover various controller specific commands, like editing the X-hotbars.