Your questions is not so clear, but I will try to answer it as I understand it.
I am a native Spanish speaker so you can trust my answer, if there is a problem with it, it is due the missing information in the question, but I think we can work it out for the best.
In Spanish when you want to make any negative setence in any tense we do not use an auxliliary verb as you do in English, we simply add the word:
No before the verb, for example in:
Yo no <u>quería</u> bailar en la fiesta. (I didn´t <u>wan</u>t to dance at the party)
Mi hermana no <u>piensa</u> antes de hablar. (My sister doesn't <u>think</u> before talking)
No me <u>hables</u>, no <u>quiero</u> nada. (Don't <u>talk</u> to me, I <u>want</u> nothing)
In Spanish we Simply use the Negative Adverb:
No
https://www.goodreads.com/quotes/599702-i-wish-this-story-were-different-i-wish-it-were
Answer:
the librarian, who was also in a rock band, decided to read a book about playing guitar.
