Watch the above video or check out the forum page for installation instructions (as well as exclusive DLCs)! Don't forget to backup the map regularly - enjoy the game!
The map is built for Minecraft 1.8.8 so don't forget to update your client accordingly. You can choose between the normal map or the YouTuber's Edition. The normal download is recommended for most people but you can check out this video for more information about the YouTuber's Edition.
The map size is just over 200MB. Please be patient. In the meantime, why don't you check out the credits?