Hi Bullets - the lingo is like a whole new language, huh?! . The "bus" is really just a mechanism for going through the cycles every month, i.e. you get on a new one when the cycle ends (i.e. AF/Period begins). If you don't know what people are on about just ask on the relevant thread you are lurking on. I've found the threads on here to be friendly so I'm sure people will be happy to explain/translate what seems like gobbledegook!
The first day of your period is CD1 (cycle day 1) visualise.
So if you get a BFP on the day your period is due, that would be CD28 - or however long your cycles are. Mine are 29/30 days for example from first day of period, to last day of cycle before next period.