If it's a stmp file, I suppose it's a multitrack project. Go to the File menu and select Export>Export Mix. In the window appearing, you'll be able to select the bounce as AIFF, SDII, WAV or AAC but not mp3. If you want a mp3, use AIFF and use iTunes to convert it.
If it's a stmp file, I suppose it's a multitrack project. Go to the File menu and select Export>Export Mix. In the window appearing, you'll be able to select the bounce as AIFF, SDII, WAV or AAC but not mp3. If you want a mp3, use AIFF and use iTunes to convert it.