I had an opportunity to stop a bus driver who was on a break to give me a demo yesterday. It is easy indeed!
The racks that my local transit uses are the staggered type. Basically each rack is biased away from one another left and right sides. This will help with mounting and dismounting of the rear rack.
The driver also advised to use the rack that is positioned to the right of the bus as it is away from vehicles that would pass by on the left.
I gotta try it one day. I am wary of bike theft though. Maybe I should just ride my beater mtb for now.