Hi. Can someone please help me.

I’ve been trying to find information from Google about <a href="https://play.google.com/store/apps/details?id=com.glow.android">tracking ovulation</a> and it’s not making much sense to me. I 100% don’t understand all the different CM and I’m not the best at tracking my BBT. Also how does the OPKs work? When you hit your peak on the tests have you ovulated that day or is is 24 hours after??

Can anyone please give me some information in the simple terms please?

Thanks in advance!!