How the balls does modding Total Warhammer work?

[KicklerOfButts]

The tutorials and resources available to understand Total Warhammer 2/3's scripting is garbage and utterly incomprehensible if you don't already know what it means before reading them.

Are there any experienced modders of the game on here who'd be willing to explain to me how to do some very basic things I need for a mod I'm working on?

What I want to do is, when a turn starts while you're playing as the Chevaliers de Lyonesse, a message box should pop up with some text in it.
That's literally it for now. I mean to do more things later but for right now I literally just want to pop up a damn event screen with some text on it, and I can't even figure that much out with how mind-numbingly obtuse the scripting API is.

I already have a functioning listener that triggers at the start of every turn as the faction you need to play as, but what now?
How do I pop up an event screen? Do I need to have the text that should go in it pre-written in a database? Where? How to access it? How does it work?
Where the **** are the UI assets used for event boxes even located? I can't even find them to use them!

Literally any help at all would be infinitely appreciated, I've been banging my head against a brick wall for 3 days straight by now and barely gotten anywhere at all.