Birth Control Pill questions

Alright so I’m new to the pill, I’ve just started taking it (about 3 weeks in already). I’m taking Estarylla and I have some dumb questions.

Exactly how precise do you have to be when taking the pill on time? (Minutes, hours?) I know the more exact you are the better protected you’ll be. But is 15 minutes off of my time going to kill me? 30 minutes? Or an hour?

When is it the safest time to have unprotected sex while on the pill?