Hello Piccolo,
Welcome to the Forum, it's a wonderful and warm place.
I'm not familiar with the book you're reading and don't know how well it explains transits (if it does at all).
A "transit" is where a planet is now, in relation to your birth chart. In order to identify which planets are having an effect on your chart, you first need to be familiar with aspects (how far one planet is from another in degrees). How comfortable are you with identifying aspects?
Here's an example of how to identify a transit:
Each sign has 30 degrees, from zero to 29, so if you're born on June 4 (of any year), the Sun in your chart is 13 degrees of Gemini.
Currently, transiting Saturn is at 10 degrees of Gemini, meaning it's coming up to that 13 degree mark soon...but it's actually in "orb" of conjuncting it now (five degrees on either side).
Currently, transiting Pluto is at 17 degrees of Sagittarius and is opposing (180 degrees) the Gemini Sun.
Yes, you will need an Ephemeris to ascertain where the planets are. If you go to:
www.zodiacal.com and click on ephemeris, you'll find one for 2002.
This is a little complicated at first until you get the hang of it. Any questions, please ask.
Regards,
AG