What are the steps best taken to take a story and make a major motion picture?

I've got a story about commercial fishing in Dutch Harbor and I am wanting to know the best steps to take in order to go from telling the story to a major motion picture.What are the steps best taken to take a story and make a major motion picture?first you need and agent without that yo are basically screwed before you start then you need a screen play so that it can be evaluated then you and your agent need to be able to parlay that into a meeting with someone who as some say in the scripts that this studio accepts after that it is up to your agent and the studio to work out any kind of a deal if they take it do you get to work on the rewrites, do you sell it outright, do you get something upfront and then something n the other end etc etc agent first otherwise getting into see anyone is a joke unless you get damn lucky.