Insert a recordable data minidisc into your multitrack minidisc recorder and turn the unit's power on. The disc does not necessarily need to be blank, but be sure there is enough free space on the disc to record your tracks.
Connect your microphone or instruments to the multitrack minidisc recorder using the appropriate 1/8-inch or XLR input jack and cable. Play the instrument or sing/play into the microphone to check that the sound levels are correct -- you don't want the decibel meter to read any higher than 0.0 decibels. Adjust the input levels accordingly.
Insert your headphones into the multitrack recorder's headphone jack or use the "monitor out" jacks to send the signal to external monitor speakers. If you're using a microphone, you will want to use headphones to monitor the sound so that your microphone doesn't pick up the monitor playback. Adjust the headphone or monitor output levels until they reach a comfortable, clear volume.
Record your first track of audio to track one on your multitrack minidisc recorder. Different machines will have different ways of doing this step, but generally, you'll need to assign the input jack (to which your microphone or instrument is connected) to track one on the minidisc, press "record," then "play" and start playing. Consult your specific recorder's user manual for details.
Listen back to the first track you recorded to make sure that everything sounds the way you want it to. If you are satisfied with the recording of your first track, repeat step 4 of this tutorial for each subsequent track, assigning the correct input to track two, track three, and so on -- until you have recorded all of the parts of your song or piece of music.