There are many ways .... you can either add a watch folder or navigate to it....
- Go to Music > Files
- Select Add Source
- Select Browse and browse to your music directoy, after adding the should be replaced by your path to music directory
- If you have more directories to add, select add and the browse, you should now have two entries to your music path
- Give Name below Enter a Name for the media source, say Music Local
- Select OK
Now you'll get a Music Local in your Music> Files
Highlight it, Press 'C' and select Scan for new Content
to update library on startup [in case you are frequently adding songs, tough i dont recommend if you have a huge llibrary]
System > Music > Library
Select Update Library on Startup and enable it.
For Videos Steps are pretty Much same except
after step 4 you may encounter a pop up of SET CONTENT
4.1 Select wether that folder contains Movies/TV Shows/Music VIdeos,
4.2 Choose a Scrapper, IMDb for Movies, TVdb for tv shows are preffered
4.3 Enable Run automated scan
4.4 Edit the the movies in sperate folder as per your arrangement in folders [eg, say you have a movie folder called moviez, and you store all movies in that folder than disable that option, or else if you have a seperate folder for every movie inside the main Moviez folder leave it enabled]
4.5 Leave Scan Recursively Enabled
4.6 Exclude path from library update [select as per your needs].
Now press ok and resume as usual
Note: Videos may update immediately and you may not have to press c and scan for new content.
I made a video on youtube way back XBMC Eden Preview, the comments might help you a bit.