If you know most/a lot of this please excuse, but I thought it might be helpful to someone to have a quick guide in one post
. Anyone who spots any mistakes please feel free to correct!
If you mark down the first day of your period each time you can count the days to your next period and get to know your personal average cycle length, after a number of months. The average cycle length is 28 days. The average day of ovulation is day 14. The days that follow ovulation are known as DPO. The two weeks that follow, from days 15-28 in the average example, are what's known as the 2WW (two week wait).
To pinpoint ovulation accurately, you could take your temperature every day (plenty of info online, but in brief you need a suitable thermometer and must take waking temperature orally, vaginally or from behind
not in your ear (unreliable)) and/or use ovulation predictor kits (OPK's) you can establish the day you normally ovulate in your cycle after a number of months spent tracking. With temperature, you are looking for a shift upwards which will show that ovulation has occurred. However the shift can happen 1-3 days after ov so that on its own does not pinpoint ov (eg it's not as simple as saying ov happened the day before the shift upwards).
Although the average day to ovulate is day 14 in a 28 day cycle, obviously this varies. It's not always 14 days just like it's not always 28 days in length. This is useful to know because some women might have a 32 day cycle and not ovulate until day 19, but assume ovulation to be occuring on the more common day 14. In which case they won't be DTD (doing the deed!) or BD (baby dancing(!)) at the right time, especially if they are not tracking their cycle.
When you ovulate, the egg lasts for around 24 hours. Sperm can last up to 8 days (apparently, however it's rare) although the closer to ovulation the sperm can meet the egg, the better and generally more successful the outcome. Sperm living so long is why you can get pregnant long before you ovulate. That's also why some women are "sure of their dates" (ie know when they had sex) but are confused when the scan shows a later date (ie the egg fertilsed 5 days after during ovulation, rather than on the night they had sex).
Hope this helps 