I am not sure what exactly you want to know about research. Basically, if you have published some articles, it is a good thing on your CV. As far as exterships go, some US hospitals offer opportunities to work with them for a small fee under supervision called externships. It is somewhat like an internship but you are not paid. In fact, you may have to pay a small fee for the privilege. It is a bit hard to find these spots for IMG's. However, you can also do an observorship in a hospital or clinic and get some good US LOR'S. You should think about these after you complete your steps so you are not too deviated.