How do i know when ovulation happens? and when implantation takes place?

Ovulation happens: 1) around CD 14 in a 28-day cycle, or 2) about 14 days before your period in a non 28-day cycle, and 3) within about 24-48 hours after first positive on an OPK, and 4) when a follicle is about 16-18 mm on ultrasound in a natural cycle. Also about 36 hours after an hCG trigger shot. Implantation happens no sooner than 6-7 days after ovulation, but there's no way to detect until a positive test.