Motor nerves are very simple: they transmit instructions through your brain to achieve certain purposes. For example, if you want to write something, you have to use your brain first, and then your brain transmits information to your hands so that your hands can type and write things out. If your hands are on the keyboard and your brain is idle, your hands won't write anything on their own.
Autonomic nerves are not hard to understand either. Think of things like our breathing, our heartbeat, and the peristalsis of our gastrointestinal tract—things that happen automatically without our brain having to consciously direct them. Those belong to the autonomic nervous system.
Most of us who practice martial arts constantly temper our motor nerves while neglecting our autonomic nerves. The stuff in the document you sent me tells us how to control the autonomic nervous system. Once you reach a proficient state, you can control your own heartbeat and gastrointestinal peristalsis.
Chapter 235