Question about modding and Steam

[Naja]

I intend to buy Empire: Total War off of Steam. I'd also really like to mod it.

From what I understand, Steam automatically applies any patches when you log in. If this is the case, wouldn't it mess up the game if it was updating modded files?

Or would it not update the game at all, and prompt me to put in the vanilla files first?

I'm a little confused.

[alpaca]

It replaces the vanilla files. Unless you overwrite those (which you shouldn't) your mods will be fine unless the patch changes something in the format of a used file.

[Naja]

It replaces the vanilla files. Unless you overwrite those (which you shouldn't) your mods will be fine unless the patch changes something in the format of a used file.

How do you mod the game without writing over the vanilla files?

[alpaca]

How do you mod the game without writing over the vanilla files?

You create a new pack file and put the relevant files into it.

[Naja]

You create a new pack file and put the relevant files into it.

Is there a tutorial for how to do this?

I'm sorry, but from what I read, ETW sounds ridiculously hard to mod. Much more complex than MTW or RTW.