Best time to conceive

Ok, so getting myself confused and probably en route to obsessed! When is it best to have Sex for trying to conceive? I’ve been peeing on ovulation sticks (Clear blue digital) and get the “ovulating soon” and the “you’re ovulating”. Is it best to have sex on the soon, on the ovulating positive or day after? I know you’re supposed to just go for it over that time- but sometimes it’s just not possible, so want to understand when gives the best chance for pregnancy.

I’m a few months away from turning 40, and feel time is really ticking away and want to give myself the best chance possible.

What are you’re opinions?