Final fantasy ...plzzzzzzzz?

now..i'm quite new 2 the gamin' world...i was searchin' on my space 4 some videos 4 evanesance and found some songs played on clips of FFVII :advent children...sure gave me the wrong idea that cloud is in love with tifa...but ireally liked them...so i just downloaded the film..(with the notice i know nuttin' about the story)but i was interestded so....disapointed cuz cloud wasn't in love with tifa...actually liked aerix more...so decided 2 even get the game...the complete game that explains it all ..i understood alittle about the story but not it all...and what's the role of zack...all tose stuff...so pllzzz i don't want 2 seem 2 be upsest with FF But i think it is really good..so any ideas where can i download the game....and which game...thnxxx aloooot!