Downloading Maps

If I download a map,where do i download it to? Also it is going to be a zip folder. Then what do i do with it?

You place the map (would be a .bsp file) in your esf/maps folder to use it. Also, if the map uses any custom .wad (texture) files, place them in your esf folder.
Most files come as .zip archives, and they can be opened with <a href="http://www.winzip.com/">WinZip</a>. Sometimes files are .rar archives as well, use <a href="http://www.rarlab.com/">WinRAR</a> to open those.