I tried to load a new map, but after I create4d one with the script placer, it would not show up in the launcher.  I think its because the file is not in the correct rrot directory. Where do I need to put the file?

On the script placer go to options/ select root directory
If you have the game on steam  this is the directory - C:\Program Files (x86)\Steam\steamapps\common\Call of Duty World at War
If you have a free downloaded copy of the game - 
C:\Program Files (x86)\Activision\Call of Duty - World at War   //this is the directory usually, but it depends where you download it, you can find the root directory of cod waw by right clicking on the icon on the desktiop and then click open file location. That's the root directory of cod waw.

If you want the Launcher location, it is located in the bin folder of the root directory.
If you want the mods location, they are located on - C:\Users\YOUR USERNAME\AppData\Local\Activision\CoDWaW\mods

Thanks so much.