The standard way to do it is an 8 hour eating window, which I think for most means just skipping breakfast and eating between 11.00 to 19.00, then 16 hours off.
I think it's supposed to be a daily thing.
Personally I aim for 18.30 to 8.30 for my food free time with a 8.30-18.30 eating window, which isn't really fasting, but gives me a 10 hour eating window.
I don't do proper IF that frequently, only when I can't exercise.
I'm going to aim for 2-3 days a week of skipping breakfast and pushing that start time back to 11.00 though, maybe even 13.00.
TBH if I can get to 11.00 it's easy enough to carry on to 13.00, or even 17-18.00
It's the morning hunger that's the challenge.