Driver medical exams: What to expect?

Has anyone actually gone through this process before? I’m looking for some real-world insight regarding what the experience is like and, more importantly, where one can navigate this whole ordeal most efficiently without it becoming a total bureaucratic nightmare. To be perfectly honest, I’ve hit a bit of a low point lately—too much time spent leaning on the bottle, if you catch my drift—and now I'm being sent off to deal with this consequence.

Any bit of guidance you can offer would be sincerely appreciated...