Obtain Retro Soundinator board. Use preferred surface-mount technique to mount all components except sockets, then let cool and solder through-hole components onto board. Add crystal; sound chip is not yet necessary. 

Edit firmware descriptors to match what CTM is expecting. Edit ATtiny firmware source with a clock divider that will drive the chosen sound chip. Make sure avr-gcc and avrdude are installed, then use 6-pin header to flash 32u4 and ATtiny with appropriate firmwares. Sound chip and wiring can now be installed. 

Make sure Python and Pygame are installed. Check system and libusb permissions to make sure the user you run CTM as will have permission to look at USB devices. Uncompress CTM and run. You should see debug information detecting the board. To check, click the header of a channel labeled as "NONE" and you should be able to assign the channel to a board.

It's time to make music! You can begin to write a song in the tracker, or load an existing one that is supported by the input filters.