The Scenario is that you can play as either England, France, or one of the 3 nations I edited on a very detailed UK map(with a bit of northern france). The three nations are Scotland, Whales, and Vikings. All the units up until the the Modern age have been customized a bit, some can move further, or not as far, are more expensive or stronger

all the civs can only use certain units. For example. The vikings can't build settlers. They have 4 to begin with, they have to take over enemy cities to expand, but they are the only ones with galley's and they have them available right away, allowing them to get a headstart, but then later, in the middle ages they will be at a disadvantage with less types of units available. Things like that.

To use the map, probably click save, and save it right to your scenerios folder in the Civilization III directory.