I have just finished my period and would like to start trying for another baby. I've downloaded the flo app which is telling me the next 9 days are the days to try but I don't understand at all how this is. Sorry if I'm sounding stupid but what determines when I ovulate and how do I know if these are the right days to try to conceive? Before I had my first baby my periods were regular and started the same day each month but this year they have completely changed.