What does downloading a minecraft project do?

I downloaded a minecraft project from planetminecraft.com and i was just wondering what does it do? Will it go into one of your worlds like you built or something?

Added (1). this is the project i downloaded- http://www.planetminecraft.com/...ter-bunny/

Guest

You need to go to %appdata% in the search thing and go to.minecraft and go to saves. If the file is in a Zip file. Extract it and it should have the folder with the name. It won't replace any of your worlds and it would make a new one for the map.

JohnThom