To do what Naga told you, you have to right click on General layer, and chose add description (it's first option that opens when right click on it).
Then you'll see a window with name of the world - you can change t so it is not exactly as the name you saved your world in CAW.
Then you can add description, you can type anything, I usually just typoe in "test" if world is still not finished.
Last option is little tricky. You have to have picture that is 256x256 in size and that is 24 bit png format (it is best to have picture of your world, as that will be an icon in launcher and main menu). to get it, I use SnagIt program, but there are several other programs that can resize and save picture in that format.
After you do all that, save game and then export world. You'll find it in My Documents/EA/Sims3/Exports, and you can install it from there.