There are far too many things to explain if you have never played any incarnation of civ before. If I were you, I would just start a game or three at chieftain, and start playing. You will undoubtedly pick up many of the gameplay basics doing this. When you have more specific questions such as Golden Ages, Unique Units, and diplomacy tactics, you should come back and ask those questions. More accurately, you should come back and look for those answers, and then ask the question if you can't find them.
I'm sure each of us could write a 10,000 word post explaining many details of the game to you, but you would be hard pressed to remember 10% of those.