What is VOP and VEX?
I'm learning.
I want to make an planet render for learning purposes, and i was trying to do some glow. I created a Mantra Surface , went inside and added a glow material. I used an node to add surfaceModel and fog together to surface output, but i just get a white sphere. I tried same result. I looked at the help for glow it , it says that i need to add to glow context. What does this mean? Where is the glow context?

edit: I'm talking about the glow material in vex builder. That's what I'm trying to leran, is to build my own shaders.