It's possible to make a Haruka reservation online, then take the printout to the JR office referenced above. And there are ATMs almost directly opposite. If going to/from Kyoto/KIX, you can buy round trip tix. The whole thing is essentially quick & "painless". Then take the escalator down to the platform, but be sure that the train is the Haruka rather than the local (as we did once & had to do a change at Osaka).