Playing MIDI notes

I would like to make a simple music beat maker. where you'll have a 5x16 grid of check boxes, and the program cycles through the check boxes at a predefined pace, and depending on which box in that column is check it plays a corresponding instrument (bass, clap, high hat, snare, etc.).

All of this is easy, however I'm not sure how to play the MIDI instrument.

pseudo code:

Code:

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For row = 1 to 16
    If Checkbox(1, row) = CHECKED then
          Play "KickDrum"
          'Then user hears a "Boom" of the kick drum

    If Checkbox(2, row) = CHECKED then
          Play "Snare Drum"
          'Then user hears a "Snap" of the snare drum
Next

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