Interviewing for an UROP position at MIT is relatively easy. I first look up the professors who has research topics that interests me. Then I either emailed them or talk to them in person to express my interest in becoming a UROP intern at their lab. Next, I scheduled interviews with them. The interview itself is very lax in its atmosphere. The professor just want to you if you are really interested in their research and if you have any background skill that's necessary in their research. For many of the UROP positions though, you don't even need to have much skill in their research area since it's often cutting edge anyways.