Roland TD-17 - How to Import Custom Samples & Use Sub/Main Instrument Layers

As a new TD-17 user, I was a little disappointed with the sounds that came with the module, and decided to import my own sounds. Since the manual does not give you a lot of information on how to use the sounds you import, I had to work it out for myself. I thought it might help other users like myself if I made a tutorial on how to do this. (Apologies for the way the samples sound in this video; when I was making the video, I had the TD-17 plugged into a PA and the way the sound was picked up by the video camera is way worse than it actually sounded in the room!)