BBT help?

Kayleigh ⛵ • 20 y/o. PCOS. TTC first baby 🍼👶🏻 since Jan 2019.

This is my first cycle tracking BBT and I have no idea what my chart should look like and <a href="https://play.google.com/store/apps/details?id=com.glow.android">tracking ovulation</a> with it etc. The app says I was meant to ovulate about 3 or 4 days ago but using LH strips, theyre all still negative, however have only been testing once a day about mid-afternoon and 2 days ago i decided to not test at all. Could I have ovulated and not known due to not testing as much as I should? If anyone can help me understand this whole BBT thing I'd be very grateful 😂