Jon,
I guess I am somewhat confused too. I'm not sure exactly what you're trying to do. I'll try to give some suggestions anyway. That should get you past "somewhat" to "totally" confused. It's my specialty.
bytes cannot be negative. They range from 0 - 255.
If you want to declare an array of bytes you need to have brackets: byte [] num;
It also would be a good idea to put some data in the array:
byte [] num = {2, 4, 3, 127, 18 };
It should be num % 2, not num % "2".
num % 2 == 0 as an expression would be true if num is even, not if it's negative.
That's probably enough to get you going. You want to start slow with programming. Arrays are a difficult concept.
You should make sure you understand the earlier principles first. It's frustrating, but worth it in the long run, to give yourself a solid foundation on which to build. Good luck!