informal rush

Hey, I'm a freshman and was wondering how I would go about joining a fraternity this late in the semester. I wasn't able to come over the summer and rush but I know the frats do informal recruitment and was just curious as to what that was like and how it all works. I know the frats have forms you can fill out on their websites, but I didn't know if those were actually looked at and how I should contact a member. I also didn't know if there's also a spring rush that I should just wait for or would I have to wait all the way until sophomore year? I know it would be difficult trying to join one right now with Homecoming and everything. So basically I was just wondering if I should wait until the end of the semester or during spring time? Also, what are my chances of getting in a frat if I go the informal route? Can anyone describe what it's like?