when you reboot, nscan will scan your music directories. You can also point your music directory to another folder in the /etc/nghost/nghost.conf file. if you have a large library, be patient. you may want to disable nscan from scanning on startup in the /etc/matchbox/session file.
If it's a little temperamental, fear not, we are working on a new player for nghost3 that should take all your scanning worries away.