Installation guide:

1. Go to your Crysis game folder -> Electronic Arts -> Crytek -> Crysis -> Game -> Levels.
2. Eventually backup existing levels with the same name.
3. Copy the level folder from the downloaded file into the current game folder (Game/Levels).
4. Start Crysis
5. Open console and type in "con_restricted 0" (without "") to allow access to console commands
6. Load your custom map by typing in "map mapname" (Without "") and press Enter.