THIS IS CONFUSING

Eva-Lorae
So I am looking at the top of the chart at the DPO section. My question is why is the DPO right BEFORE the day that is predicated to be my "O" day? Doesn't that O stand for Ovulation? If so how is the DPO BEFORE that day????
Please help!!!! 😡😡😡😡😡🙄🙄🙄🙄