well, first the understanding of the i and i/namaste ideology. also, rastafari believe in living as "natural" man; a purity of body and mind, a natural state of mind.....lets say, un conforming. non conforming to the laws of man. where one lives by the natural laws of god... to use reason, to look within for spiritual answers, for world view... to look within so one's view is not clouded by the programing of society; the smoke, of altered text books; the negative and detramental way in which modern "pop culture" lives.
a wordly quest of unity, for all mankind; to look for inner peace here, on earth, within ourselves, before we can expect a great god to "enlighten" us, to come down and save us from ourselves. peace and understanding will come from within. with personal enlightenment, "god" will "show itself" (so to speak). these are the ideals rastafari has shown me in the past. and i liked these ideals, thus i adopted them. and with time, the meanings become more clear. (my interpretations may be "off", but that makes little difference)

to answer your second question:
when i first listened to raggea music, it was as if i knew the music already. as if the beats and melodies and lyrics already played in my head, long ago. it was a nastalgic feeling, and peaceful. i fell in love with the music instantly. i became curious to learn more about where this music, and the message was coming from. so i did some research. much of the rasta religion means nothing to me, but many of the fundamental ideals touched me.