Congrats to you!
As it's been mentioned above, it is a fairly long process. It will help if you know of real life students or nurses from your country and have successfully gotten thru the USA processing system. Hope you can ask them for some assistance.
In many states, you will need a SSN to even apply and some require that you are already licensed nurse from your country and will need a copy of the license for verification.
Since the US is very large, what state(s) do you plan to start work in? To be a traveling nurse, I think you must have at least a couple of year's of US RN experience.