I agree read both the sponsor and sponsored person's country specific guides and print the checklists off for your application, they tell you what is needed. Based on my experience, I'd read them THOROUGHLY more than once and send everything right off. Somethings some people wait for like medicals and police certificates. But I would advise against it. Mine was lost 4 months after I sent missing stuff back in and with all the trouble they're having I wouldn't do it.