What can and can't the World builder do?

[Orion43]

Hi all, a couple of questions from a newbie about the World builder if none of you mind. Am I right in understanding that:
1. The world builder is accessed only from inside the game?
2. That the only things one can do in WB is change the shape of land and terrain, place the locations of each civ's settler's, cannot change the size of the world?
3.The manual states that there should be folders within game directory that explains how to use the WB, XML, and Python. I couldn't find it.
4. What is the difference between a mod and a map?

Thanks for any help.

 

[Depx]

1. I think so, havent used it.
2. Dunno, but I would assume so.
3. I'm not sure, but if you open files like python and xml there is info inside that explains what different parts do.
4. Mod changes the way the game is played, map is just where you play the game.

 

[Kieran]

Can you only see the topmost unit on each tile?