I use fertility friend too!
Just take your temp first thing every morning at the same time - before drinking, peeing, talking, etc... You can either graph it yourself or put in in FF (which will graph it for you). Before o you will see lower temps, and after it will be higher, due to progesterone (called a thermal shift).
As Tasha said, Ovulation day is the last day of low temps (fertility friend will put a red vertical line on that day so you know.) Then, when your period starts, you can count how many days from O to AF to know your luteal phase.
If you have no thermal shift, that means no ovulation (if you are charting correctly).
My chart is in my siggy - this cycle just started for me, but scroll down to see last cycle & you will see a clear thermal shift & temps dropping on AF day 1. And with a BFP, temps will stay up.