I applied online. The process took 1+ week. I interviewed at BorderLink (Tokyo) in Jan 2019
Interview
Very simple process. Online Application form completed, brief email correspondence to schedule a Skype interview and a pretty standard ALT interview. I turned down the position for a better offer but it was a very easy interview. Had to come up a lesson demonstration on the spot.
Interview questions [1]
Question 1
Why do you want to come to Japan? How would you deal with unruly students?