Find and study every take down and snake bow build along you can find on the internet until more confidence is achieved. Obtain the basic tools that have been mentioned. Get scraping and shaving on those billets. If your concerned about the direction you should take at any point, there are so many here that will be happy to help guide you in the process of turning these billets into a bow, take pictures and ask questions.
Success or failure at the very least it will be a learning experience. At the end you will have a bow or you will have firewood. This is the reality of making wood bows. If you succeed you will feel more accomplished than you will if you had someone do half the work for you. If it breaks, try to figure out why it broke and learn from it.
I did all the research I could before I started making my first bow, and came to the conclusion that I wouldn't know I could do it until I turned a piece of wood into a bow. I went into it feeling like my odds of success were pretty low, I expected to break a couple before I got one that would work. Lo and behold my first attempt became a bow, and I was very happy with this accomplishment. A snake bow takedown would seem a bit intimidating to me. I would probably go out and cut myself a white oak or maybe find a nice piece of snakey wood and attempt that beforehand to build my confidence in it. I have also not worked with osage yet, but I would try to chase one ring at a time even if it wasn't the ring I was going for, the idea being that by the time I get to the ring I was going for i'd have a lot of practice. Try to learn as much as I could throughout the process so that if I broke it, the knowledge I gained from the attempt wouldn't have made it not a total loss.
