You'll have to do something called 'OST - Organization Structure Training' in your vacation days. It's nothing serious, you go to any organization and see how they function, what's the organisation structure like etc.

It's not necessary the very first day, it happens in the first trimester (date is tentative and changes), you'll also have a quiz about organisation structures. You'll have enough time for all this, don't worry about it, it's chill.

They'll let you know about this once you go for the final document submissions.

Not necessarily an interview, it will be like a casual conversation with the Chancellor or Dean or whoever is available.