1. Make it as a "real audio CD": choose "Audio CD" in Nero, drag and drop(or add) your MP3 files into nero window, burn it.
This CD can be read from most of the audio hi-fi, but the sound quality is not as good as original CD, since information is loss when comply into MP3 before.
1 normal CD can store about 10-16 songs(depends on the length of your songs).
2. Burn MP3 files into a Computer data CD : Choose "data" in nero, drag and drop(or add) your MP3 files into nero window, burn it.
This CD can be read from most of the newer DVD player, sound quality is not as good as original CD, but this method can store about 150-200 songs in a CD(assume 4MB per song)