In Louisiana, where can I get the necessary documents to begin the divorce process?

My wife and I have been separated for a week or so, and now I'm ready to start the divorce process. The way she was talking I thought for sure she would have already done this, but she hasn't. I've never been around a divorce so I don't know what the first step involves. I'm guessing there is some paperwork that needs to be filed, but I don't know where to get these documents. Are they available online? Are they free? Where do I submit them once I have them filled out?