Ovulation usually occurs 2wks after the 1st day of your menstral period..everyone is different though and the best way is to use Ovulation prediction kits to help pinpoint ovulation and lets you know the best time to have sex for conception to occur..
You can google ovulation and it will give you more info on how to check for ovulation..
Good Luck!
I would start having sex every second or third day, right now if you haven't yet.