moved docs around

extra-docs.md

@@ -1,3 +1,25 @@
+## Importing an existing iTunes library
+
+In iTunes 12.x: **File ▸ Library ▸ Export Library** to get the XML, then:
+
+```sh
+lintunes --import-xml "iTunes Library.xml" \
+    --music-root "/path/to/iTunes Media" \
+    --data-dir /path/to/library-data --save-config
+lintunes                                  # from now on, just run it
+```
+
+This brings across your tracks, playlists, playlist folders and smart playlists
+(auto-updating and still editable), along with play counts, ratings and dates.
+Mac paths are remapped to `--music-root` automatically, including
+case/accent differences. Anything it couldn't find is written to
+`import_missing_files.txt` in your data dir. Untested on iTunes versions other
+than 12.
+
+
+
+
+
 ## Mac or Windows?
 
 LinTunes is only built and tested on Linux and