how exactly does cob usually work?

So I rushed in the fall and dropped pretty early due to a health issue, and it really upset me a lot because I was really excited to join a sorority and have that sisterhood. A friend of mine from high school is in a sorority that I like a lot (I know a lot of girls in it from my hall, my older sister's friends, etc) and I seem to get along with them very well. She told me that she did a recommendation for spring COB for me. I don't want to hound her about it or anything so I was hoping someone here would be able to tell me. What's usually the next step? I've heard of some simply doing interviews and others having multiple COB parties. Would they be pretty soon? Thanks!