Instruments are the sounds used to create music.  You must load an instrument into a song before it can be used in that song.  Instruments can be loaded by choosing ‘Load Instruments’ from the Instruments menu.  MacMod Pro supports the following formats for loading instruments:
    ‘snd ’ sound files (system 7 sound files)
    MacMod Pro instruments (consists of the actual instrument plus all looping information)

Instruments can be copied, cut, pasted, and cleared using the Cut, Copy, Paste, and Clear items of the Edit menu.  If you have an instrument in one of the clipboards, you can play it through the Clipboard window.