i have read many books i have a few by adam kadman and a few other people. i have reand and printed tons of stuff from the net and i have even tried playing through a few books. but i still dont seem to get it.

key. i know every peice of music is in a certain key. if you listen to classical (i do some times) youd know that noctrune by chopin has been played in every key under the sun.but i still dont see how the key applies. i know that when you know the key you cam play the mode or scale that goes with that key or that accents the key (ie bm key play your scales and modes in em, the cricle of fifths????) kinda of thing. but how in the world does this help while playing a song like black dog or enter sandman? is it as long as you know the key and chord progression you can fake it?

every thing ive read said know this will make you a better. but i dont think they have ever really explained or im just dense and its not soaking in. any help would be great cause im lost right now.