K guys follow all of these directions to the tee and you should be able to check out all four skyboxes :)
*Do all of this before opening Radiant..this is important :)*

1.  Open zip.  Double click on PK3. Extract all of the skyboxe's PK3 contents to a pretty empty folder, and you will see three folders (1) env (2) scripts (3) textures.

2.  Now put the "env folder" into your "Q3Arena/baseq3 folder".

3.  Now the rest are self explanatory.  Add all of the folders inside the "textures folder" I sent you into your "textures folder" under your "baseq3 folder." The folders you should now have added to your "baseq3/textures folder" are "Malrav1," "Malrav3," "Malrav11," and "callystam11."  Inside of each are the application textures. Next do the same process with my "scripts folder."  Add "Malrav1.shader," "Malrav3.shader," "Malrav11.shader," and "callystam11.shader" from the "scripts folder" I sent you to your own "baseq3/scripts folder."

4.  Now still in your "baseq3/scripts folder" you will see your "shaderlist text."  You need to open your "shaderlist text" and add the words Malrav1 Malrav3 Malrav11 and callystam11 to the bottom of your "shaderlist."  Now save it and close it :)

5.  Now that this is all done, you can open radiant.

6.  Once open make a simple room with and "info_player deathmatch" in it somewhere, and make a big box around the test map you created with the common\caulk texture (little pink one).  Do not overlap the edges of the outerbox.  Have all corners just meet one another exactly.  That way you won't get mismatching skybox edges due to the edge areas being covered by the one of the other wall sections.  See what I am getting at.

7.  Now go under the "textures menu," and you should see "Malrav1" "Malrav3" "Malrav11" and "callystam11."  Pick one...Lets say "Malrav1."

8.  Now you should see a little blue texture called "malsky5."  This is the application texture.  You do not see the skybox pic.s in radiant..just the blue application textures.  You will see the pics when the map is compiled :)

9.  Now go to the "plugins" menu and open up "curry"  It will load all of your shaders.  Now find "Malrav1.shader" and click on it, then click on the shader description that appears below it.  Now close curry and click on your textures window (where you loaded up the little blue application texture, "malsky5").  You will see another blue texture with a thin white line around it appear with a name like "Malrav1_skybox."  This is your skybox application texture :)

10.  Now select the face of one of your outer box walls (shift + left mouse click), and apply the application texture "Malrav1_skybox."  Repeat this for all six of the inside "outerbox (outerbox just means the box you made outside/surrounding your test map, also called skybox)" faces.

11.  Go up to BSP and do a fullvis compile (Fullvis -shorter compile- or Fullvis -light extra -longer compile, but looks better-).  Do not do fastvis or fullvis -nolight seeing that they do not produce the shading/shadows that make the skybox colors rich, since they set your map at fullbright. 

12.  You can now load up your map and check out your new skybox.  Try this with all of them.  Take care, and hope ya like.  Also please don't take offense to the simplicity of this tutorial if you already know most of the stuff I explained ad-nauseum :), I am only trying to make sure you get it all right because they are confusing to do the first time :)
Ford. 
