Help please, I want to create a scenario.

[salty mud]

Hi I want to create a new scenario to play. My scenario will be about Julius Caeser in Gaul, fighting the gallic tribes and Vercingetorix. I have some questions;

1. Using the WorldBuilder and a custom map, can I alter the terrain so I create my own world? (Gaul?)

2. How do I change factions colours?

3. How do I install custom leaders heads in the select an empire screen?

I'm a total modding noob so I will probably balls up and have to reinstall, but I want to try!

I hope I'm not being demanding, but help would be good. Could a skinner create some units if their interested?

Thanks for your help!