Once you place the base in your town, you'll need to whack it (that is, use energy) to build up the frame six times. With this completed, you thankfully won't have to collect any building materials; rather, this is a community building that uses your friends as staff to get things done. In this case, you'll need ten friends to come help out. It should be noted that you can use any extra "Bonus Crew" - the pictures of Samantha - to staff this building for free, if you have some on hand. Otherwise, you'll need to send out individual requests to those CityVille neighbors that you think would be most willing to help you.
When this one is complete (you'll know because you'll either get an email telling you the staffing is complete, will see the hammer on top of the building, or both), you'll have a fun outdoor playground (that's of course themed to Monsters / Halloween) that allows for 1,500 extra Monsters to live in your town. Granted, this item won't help you actually add those 1,500 Monsters, but at least you'll have the room for any you want to add in your mad dash to the finish! Good luck!
Will you add the Plagued Playground to your town just for the look of this limited edition building, or are you actively trying to reach the 8,000 Monster mark? Sound off in the comments.