I applied through college or university. The process took 1 day. I interviewed at UIDAI (New Delhi) in Jan 2018
Interview
Simple and straightforward. They gauge if you can identify problems. You need not completely solve the problem, but understand the parameters pertaining to the problem and how well you structure the problem statement.
Interview questions [1]
Question 1
Have you watched MI3?
How will you stop fingerprint duplication?