I would google ovulation calculator
Download This App Called My Days On Your Phone Its Very Helpful I Used It To Get Pregnant
14 days after the start of a actual period (not the spotting days) but that can fluctuate for each person have sex every other day around the 10th day (19th-28th if your actual period was the 19Th) every other day or even every third day will be fine then continue for a few days after do not have sex everyday i was told by fertility Doctor sperm has to rejuvenate your odds will be better that way...also get ovulation kit (around $20) they can pin point the day! good luck!!