This is gonna be a bit of a doozy, please bear with me.
First, grab Anaconda (for Python 3.6) here: https://www.anaconda.com/download/#linux Follow the instructions below the download links to install it!
Then, check https://www.tensorflow.org/install/ for instructions on how to get Tensorflow working: this is the least approachable part, and depending on whether you want to use GPU acceleration, you might have a whole new gamut of steps to run through.
In addition to Tensorflow, you're going to need tflearn, scipy, and h5py (all of which
can be installed using pip install ____), as well as python3-midi, which you can find
here: https://github.com/louisabraham/python3-midi
In terms of training data, the repo comes with all the MIDIs we've found of Bach's
chorales. When you run python main.py , it should generate a network model
and go through a certain number of iterations (determined, for the moment, by the
iterations variable on line ~82 of network_model.py).