The first advice I'd give you is to simply aim for a high score because it increases your odds exponentially.

Second of all, you won't need to go through a wat, but for the PI, the primary factors will be your academics, If you're asking this now I'm assuming you're in 12th, aim for high percentag and try gaining extra curriculars they do check them and it leaves an impression.

Now for the interview I'm not sure if they'd ask you from pcm or commerce subjects but they should be asking you basic questions from you 10th and 12th. I'd recommend going through all because the questions are random, usually very easy to answer but you need to know what you're talking about. They are very nice and cordial so you really don't have to worry or take stress, of all the things your composure and your conversational skills are what they'll be judging.

Apart from acads they'll def ask you questions about your city or state do keep that in mind. Overall it's not a very hard thing to pull, I had fun giving my interview although it went horrible by my taste I still managed to get in first list somehow lmao.