Just a small problem that i would like some help rectifying.

When i try to play anything in Cubase the sound does not appear to work apart from a MIDI file, for example if i import a MIDI file and an MP3 file i can hear the MIDI but the MP3 does not make any sound whatsoever. So i would like to know how to change it so that MP3 files will play.

Apologies for the vagueness but i'm not to knowledgeable about this stuff.