How do you mod mtw?

[Bombasticus Maximus]

Can someone tell me as I'd like to have a go at it.

[cutepuppy]

Can someone tell me as I'd like to have a go at it.

what do you want to mod? factions? units? trade goods?...

take a look at the stickies on top of this page, you can find a lot of information there.

[Bombasticus Maximus]

Say if I wanted to make a mod like the featured ones whats the best way to go about this?

[Bombasticus Maximus]

How do you make it so when your general dies it does what RTW does and shows him dieing?

[R'as al Ghul]

That's a feature that was introduced in R:TW.
It's not available in M:TW.
I don't want to sound unfriendly but there're a lot of modding guides on the MTW modification forum and people have put huge amounts of time into them. If your questions are covered by these guides you probably won't get much answers.
You can also check out the M:TW mods and learn what is possible and what not.