I just want to clarify something, so the real FL of the story actually went back in time?

A secretary from from the modern world die and woke up as a character from a book she read but woke up in the body before the book had gotten to the part were the king had picked the FLs brother as secretary

Yeah, the Ella we see here was a woman who transmigrated into the body of the original FL. After she proved just how trashy she is, Kahir threw her away and she went back in time to the story now.