How do I start from scratch on the GEM map, and place cities on the map as I see fit?

Trying to do so for a 2009 AD scenario.

Basically...

Want to start using the GEM map (which I believe starts with a 50 civ DLL from Revolutions??? correct?) and manually place the cities of the world on the map correctly, and then assign the correct civilizations on the map. What steps do I need to take to accomplish this?

Thanks.