They'll basically ask you about yourself, and they give you a test. I mean, they'll literally give a piece of paper with extremely outdated Linux questions (some of them being relevant), along with a couple of basic bash scripting languages (while and for loops).
Don't even bother asking for W4 or I9 when they ask you. They'll give you an I9 regardless of what you ask for. They claimed they offer benefits, but I haven't signed a single piece of paper. Technically, I'm not even suppose to be working here.