How do I start?

I’m wanting to start a power washing driveway cleaning business, but after watching probably 50+ videos now at this point and asking AI certain questions, I’m not sure what things to buy and what things won’t be that necessary with what I’m doing. People said I need chemicals, don’t need chemicals, certain types of surface washers, etc etc.

So basically, my main question is what items should I purchase, what should I NOT purchase?
Specific concerns
- do I need chemicals?
- what size surface cleaners?
- ideal PSI/GPM?

(Also any tips and tricks would also be greatly appreciated)