I'm working on a mod with a friend.

What's the best/recommended way to work together on a mod?

I'm working on one part, my friends works on another - how do we later consolidate the information without overwriting or implicitly creating "WorldSpaceCopy"s?

For example, my friend constructed a mountain. I want to construct something near that mountain, while he constructs something else near that mountain.
What do we have to do so that we will both work in the same space?


Generally, how does teamwork work?

Thanks!