when i first started charting my cycle i used fertility friend (i still use it). it's a really great app/website. i would suggest ordering a BBT if you don't already have one. so you wait until your AF goes & every morning before doing ANYTHING (don't get out of bed, take it while you're still in bed) you take your temp, you record it into fertility friend, day by day it starts making a chart/graph, you also record the days you DTD, your CM, any other symptoms. i personally start using cheap ebay OPK tests around CD 13 as i O very late, so once you start recording + OPKs it estimates your most fertile days (it still estimates your most fertile days even if you just use your temp & no OPKs) it sounds very confusing to begin with but it does get easier... & VERY addictive; well for me anyway .. many more things too