Hi Bo - Cycle day 1 is the first day of your period. Have you had a look at the Fertility Friend site? This is a good way to learn about your body. I gave it a go when I first started on here, and it was very helpful. To work out when you are most fertile, temping with a Basal Thermometer, observing Cervical Mucous and using Ovulation Predictor Kits are good. You can chart all of these things on Fertility Friend, so that after a few cycles you might start to see a pattern.
Check out the TTC threads, they are fabulous for talking things through with others who are going through the same thing.
good luck.