Filing a LIEN on Someone's Property

I have a few questions.

I delivered material to home site for a contractor about 2 weeks ago. Contractor hasn't paid me, because he said that he hasn't been paid by homeowner. No, I didn't have an agreement to wait for homeowner to pay. I specifically told the contractor that I needed to be paid immediately, which he agreed to.

I told the contractor that I would file a property lien next week if I did not receive payment. He said that I should to protect myself.

1. What's the process for doing this? Do I need to hire an attorney to do this, or simple enough?

2. Should I inform the homeowner before I do it?

3. Other issues I'm missing?

I've never done this, and don't want to, and hope I get paid in the next few days.... but, I don't feel like getting screwed by this contractor or the homeowner.

If it matters, it's in Baton Rouge.

Thanks for any info.