After the sperm and the egg join conception, the combined cells start multiplying pretty quickly and moving through one of your fallopian tubes to your uterus. This cluster of rapidly growing cells is called a blastocyst.
Once in your uterus, this little bundle of cells has to attach, or implant, into your uterine wall. This step — known as implantation — triggers rising levels of all those fun pregnancy hormones (estrogen, progesterone, and hCG, or human chorionic gonadotropin).
Implantation takes place anywhere between 6 and 12 days after you ovulate or 8 to 9 days after conception. So the exact date of implantation can depend on when you ovulated, and whether conception occurred early or late in the ovulation window.
Video on Fertilization & Implantation: https://www.youtube.com/watch?v=3u251OXfsRU