Sims 3 Ambitions--Ghost Hunting?

I just got the sims 3 ambitions game and my sim is a ghost hunter. I don't really understand the job, and there aren't any specific work hours for it either, it's just an on my own thing. I don't undestand how to "Collect Spirits" but my sim has a current wish to collect five of them. I went to the graveyard and i clicked on a random ghost that was roaming around but all my options were "friendly intro" or "rude intro" and stuff. I clicked on a gravestone and clicked "appease ghost" and then when the ghost came out, "banish ghost" but i don't really understand what that even did. Help!?