i troed using a sky shader but it it doesn't act like a sky it just is a sky textures wall...so how would i make that brush a sky..

I found skyboxes extremely difficult at first too but they're EXTREMELY easy!
Ok...
Make a box and hollow it, this will be your skybox. Now, make your level inside it, however you want it to be. For this example, simply make another hollow box and remove the ceiling so you're able to see the other box around it...

Now to texture your skybox. Load the "skies" texture subset. You will see many beautiful images that will produce your sky, but you need to use the red & black checkered boxes (small boxes around the real images). For example, the bottom images show a countryside with a planet in the sky. Naturally, if you want to use these images, you would try to use the images themselves for textures, but no!
Select all the six faces of your skybox and then click on the red & black checkered box titled "yavin". Your skybox will now show a texture saying "Shader Missing" or something like that...
This is ok. Now simply save, compile and run your map!
You will notice your sky appears perfect!
Some skies will light up your exterior areas of your map. These skies are the ones with "_light" after their name. For example:

artus_light

The ones with no "_light" after their name such as:

yavin
or
bespin

will not light up your exterior areas, just the sky itself will be lit. In this case, use normal light entities to light your exterior and interior areas. With "_light" skies, you will still require lighting your interior areas!

Hope this helps!

Kayron James Mercieca - kayronjm@gibnet.gi

Stop with the hollow boxes! That is exactly how you are NOT supposed to do it. Just texture the sky wall you already have with the proper shader, he's got that part right, but you do NOT need a box. That's very bad, it hides leaks.

OK, you dont actually need to make a sky BOX, thats taken care of by the shader (as he says, make sure your using the actual shader, not just the sky textures). Unless you map is one of those 'box o doom' levels that consist of a few ploating platforms in a huge box, then you have no need to do this. Simply apply the sky shader to any surfaces you want to look like sky in your map.

Yeah, what JM said