Ok,to answer your questions:
1) Imagine a vacuum container. No air, nothing at all in a container. This is your antimatter. known as "space". The container it self is the Outer Dimension. Now, if you have small bubbles of air or liquid inside the container, these are planets and other areas of air/liquid. Basically "matter". Dimensions are containers of matter and antimatter. there are two sides. +Space has antimatter for space, and matter for planets. -Space has matter for space and antimatter for planets.
2) Imagine those bubbles of air. These are nodes.
Okay, lets say you have three 1-gallon buckets. your node count is 3. now lets say you pour all the water into one bucket. your node count is 1. You see, its NOT the total volume of matter or antimatter. but the separate entities.
3)The medium in math is the average or middle between 2 numbers. Say "5", and "3", your medium is 4.
Antimatter is always negative. Matter is positive. Energy is the medium
3 (1/2) Correct me if i'm wrong, but a constant is number which is always the same. Pi is an example. And i should say energy is a constant, and M-NC and M+NC aren't. But the antimatter and matter always increase proportionally so that the energy remains the same.
P.S sorry it took so long to reply.