TTC and using ovulation kit.

Melissa • 33 yrs old I have two wonderful boys and one beautiful step daughter. I`m a nurse and going to school to become a PA.
So I'm having a confusing time using an ovulation kit. I started my period on the sixth doctor told me that I'd be ovulating in 10 days over the glow app told me to try and ovulation kit today and I did and it's negative. Will I know when I'm ovulating? Dude this app. Good on pointing out my ovulation time? Should I wait till the 15th / 16th?