How to catch the 12 ghost on Sims FreePlay when?

The game itself still doesn't notify me about this?

Please help me! I wanna have the Haunted House.

P.S you're probably thinking why I know this. It's because I have another sims on my mom's iPhone.

Have you updated the new one? (version 3.1.0) if you haven't, you should. Or it won't work. If you have, go buy some furnitures that have ghosts icon on it, then click on the furniture and choose 'search for ghost' your sim will automatically catch them. It takes about 6 mins. Hope this help you