Jumping into Total War, teh moods!

[pakoito]

Hello youse,

I bought Medieval 2: Total War this Steam Xmas sale and I haven't installed it yet because I don't really know where to start + lack of time. I bought it mostly for the modding community (AGOT, LoZelda, LOTR...) but I made the mistake of not buying the Kingdoms expansion. Is it mandatory for most them?

Second, where do I start with the gameplay? Vanilla campaigns, mod campaigns, custom maps?

TANKYUS!