Many, of varying depth and quality. Here's a pretty good one oriented at first time users who are used to Windows (sadly it's four years out of date, but much of it still applies). Here's a more recent guide.
As I said, OS X is a variant of Unix, so you have to create a profile. By default you'll be an admin (not root, thank goodness). But Unix doesn't know what to do with you unless you have some sort of profile, which defines permissions and access rights.
If memory serves there's a moderately irritating video, and then you have to do things like type in your name, timezone, and a few settings. Nothing too horrifying.
The desktop and taskbar are fully customizable. If you want an app to hide in the Programs folder and never show up in your field of view, that's eminently doable.
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