I am not familiar with the book you mention Bena. No, you do not have to have 24 cycles charted, everyone has to start somewhere. You just need to be more conservative until you have some experience. Most of what I have read would be to abstain during Phase I, before ovulation, so you get an idea of your mucus pattern, undisturbed by seminal residue. You can just take temps orally, preferrably at the same time in the am, of course with kiddos that is hard. Phase II officially starts the moment you have any mucus. The most conservative rule for PHaseIII would be to wait until you have 4 days of drying up and 4 days of temps elevated to .4 of a degree above your low temp level.
So, what you are going to look for is your mucus drying up; going from stretchy egg white at the most fertile, back to tacky - meaning it won't stretch you you pry fingers apart, and eventually to virtually none. If you have a good mucus pattern, supplements can help line this out, as well as diet and exercise. Coming off the pill you will probably be a bit off for a while, if no one else gets to it, I will try to look that up for you.
For your temps, it is a good idea to take your temp every day especially at first until you get more acquainted with your cycle. Plus it forms a good habit. With your temps you should notice them start to rise when you ovulate, hopefully coordinating with your mucus dry up, but this is not usually exactly coinciding.
Sperm have been known to live for 5 days or say and the egg for 24-48 hrs. This is why it is important to abstain at first during Phase I, as you don't know how early you will ovulate and this little fellows could still be swimming by the time you ovulate. Also, this does not pin down the exact day of ovulation, but just a close approximation, that is why the wait for a few days after the temps start rising and mucus drying up.
You can check your cervix as well, and this will provide even more confidence. Also, with internal mucus checks you will have a heads up on the more fertile mucus earlier.
well, I am going on and on,
hope that has helped some,