You can summarize and paraphrase or directly quote.
To directly quote, use parentheses to separate the citation from the text. Then place the author's name or the name of the source inside, and if it is a book, include the page number(s). Hope this helps!
-Dylan (AKA Animus)
Answer:
It affected the plot because
(hospitality rules) Bellerophon had been a guest for 9 days before the king read the letter that ordered him to kill Bellerophon.
