Soozy, I use the bus all the time. Feel free to email/msn me with any questions you have. I know landmarks for many places, so I can give you detailed directions in some cases. I would suggest getting a detailed road map of Vancouver when you get here.
If you're standing at the stop the bus will stop. It just has to be more or less obvious that you are in fact standing at the bus stop and not just randomly on the street, so stand near the pole with the bus stop sign on it or sit on the bench (there may or may not be one depending on the stop).
For getting off: either you step down onto the first of two steps to get the door to open or you press firmly on the door handles. There will be signs.
The trip planning feature on translink's site can be useful. It doesn't always show the best way, but it will get you to where you need to be.