How long to go from "I can't drive at all" to driving a bus?

I can’t drive at all. how long would it take me to learn how to drive? (please no one chime in and say “depends whether you pass or fail”... duh-uhhh, I never thought of that!) and after that, how long to take to learn to drive a bus? do I need a special test for it? and roughly how much would it cost. thank you in advance for your answers.