You write the words and the acting in the same box. Short directions go in square brackets where they should happen, like [sighs], [laughs] or [pause]. A stretch wrapped in <whisper> and </whisper> is whispered. A mood at the start, like [icy calm], sets the tone for the whole line. None of the bracketed words are read out; they only tell the voice how to perform. Then you pick who speaks: clone a voice from a short clip, describe one in plain words ("gravelly old sea captain, slow, salt in every word"), or let the model invent one.
What is new is the retake. If a line comes out too gloomy, you write a note such as "more amused than before; drop the hurt" and it performs the same words again, judging the note against the take you just heard.
The same model handles whole scenes. One script can hold up to 16 characters, each line labeled with who is speaking, and long text is split into chunks and streamed as it is generated. It can also correct a finished line: give it the old take and the fixed sentence, and it reads the change in the same voice.