So, you have downloaded a map and want to play it, but you don't know how. This is what this thread is for. READ ON!
Tutorial (Green = Important)
1. Download the map that you want to play
2. Most maps come in ZIP or RAR format with the map inside
2.1 Right-click on the icon, go to Open With > WinRar or any ZIP opener OR right-click on the icon, go to Extract Here and a folder should pop up with the map name wherever you saved the ZIP archive
3. You'll need to navigate to your .minecraft (if you don't know how, read on)
3.1 Click on the Start button in the bottom-left corner
3.2 Type in the search bar: %appdata% (XP users, click on Run and type that in)
3.3 Double-click Roaming, or just hit enter
3.4 Go into .minecraft (Usually at the top)
4. Go into Saves, which is where all your worlds are
5. Drag the folder (NOT the ZIP or RAR Archive) into the folder, not one of your maps already made
6. Play your map on Minecraft!