after you do your BBT for so long you will know when you ovulate by a drop in temp, and it can tell you if you possibly have implantation happening. Check out Fertility Friend, theybhave a run down of it and . its a great app to put your temps in
It's your temp before you get up. So you take it right as you wake up your temp will be a tad higher when you are ovulating.
@xoxo512070, thank you so much