Thank you for asking!
Technically The Twilight Throne will cover just the absolute basics of Forged in the Dark, so some of the more in-depth things (like why Flashbacks are cool and such) won't be present.
That being said I'm thinking of adding a little more, so that folks won't have to reference two books in order to play this game! It's just a little tricky when things are still relatively in flux for the mechanics...but I'll definitely do my best!