Rekordbox import a map from pc to rekordbox

That's correct - the folders themselves don't show as such; you can drag-and-drop a folder of songs into a playlist (which you create first), and that would populate the playlist, or you can enable the EXPLORER view within the preferences so you can browse your computer's folders as they are organized on your hard drive, and any files already imported / analysed will appear with a rekordbox icon (or CUE icon if they have cue points).