Help ttc after stillbrith

Lashenae

I’m trying to conceive and I downloaded this app to help keep track of things , can someone help me with understanding how it works meaning if day 15 states 7.4% and day 21 is 27% and day 24 is 8%

I need help in understanding that and what percentage is the highest to conceive

Trying after having my son stillborn Jan 13 2017