I would suggest you do some research on what documents are necessary or hire a consultant to advise you before you come....
Focus's comments are sound, except I don't think you necessarily need to pay someone for advice before you get here.
In my experience, you can ask a question or two at least via email, of an immigration attorney or facilitator gratis.
Is it my imagination...or is Focus a dead ringer for the brilliant North American character actor Joe Pantoliano?
cccmedia in Quito