Open a standard MIDI file in a sequencer or notation program. The file extension for standard MIDI files is "mid", but other extensions such as "kar" and "smf" are also used. In addition, many commercial music programs have proprietary file extensions such as "seq", "not" or "enc".
Go to the track view. Most sequencers have several views or windows with dialogue boxes and other configurable items. The most convenient way to view multiple MIDI tracks is to view them in the track view. If you assign MIDI channels using a notation program, go to the staff-setup window.
Highlight a track to be edited and go to the column labeled "Channel" or "Ch". Some sequencers have a drop-down list that displays MIDI channel numbers 1 through 16. Other sequencers allow you to type the MIDI channel number into a box.
Select the desired channel number for the highlighted track. You might also wish to assign an instrument for the selected channel. Depending on the sequencer, you can also set up values such as volume, pan, and key (transposition).
Highlight other tracks and assign a MIDI channel and other parameters that your sequencer offers. Remember that you can assign up to 16 MIDI channels.