I have figured out most things just by playing around and reading the tutorials on this site but aa few things still elude me. What exactly is a "shader"? Is it the same as a texture? I usually hear them said together but iver never really heard a definition at all. What is the easiest way to make a set of stairs? is it to just draw the brushes out the grid or is there a specific way to do it in GTKRadiant? I saw something in the manual that helps you make a spiral staircase but I just want a straight up-and -down type.
Thanks for all the help

Shaders...

Let's say you have a texture, and it looks like a squarish light fixture.

A shader is like an 'information' script that the compiler uses to give that texture extra function. For example, the shader can say, "this texture has a surface type of glass" -- so when you shoot it, there's glass fragments that fall. The same shader can also say, "this emits light, at this intensity, with this color".

Shaders are, essentially, little scripts that you can attach to textures, to give them more information than just their original visual appearance. Does that make sense?

yeah alot of sense :) thanks for the reply