As much as I'd like more people to build it, I don't think it's a good match for your situation. Both things that make the ottopot special (and thus a bit more involved and expensive) won't work with hardware synthesizers as far as I'm aware; 14bit CCs and MIDI feedback for updating the LEDs. I think your best way forward would be to buy something like an Arduino starter kit with a handful of components and a breadboard and just start following some examples from arduino.cc — probably using USB MIDI at first because it doesn't require any additional components with modern microcontrollers. From there it's easy to go to DIN MIDI. Overall I've found MIDI projects a very good entry into the world of electronics and microcontrollers because it's really simple and even the smallest projects can have immediate, motivating results.