The friar instructs the nurse to go to Juliet's chamber to comfort her and ensure she is ready to go to church for her wedding. He also tells her to keep Juliet's secret marriage to Romeo confidential.
they say she must marry or move out.
The Nurse and Friar Lawrence knew about it before anyone else because the Friar performed the marriage and the Nurse was Juliet's close confidant so she told her everything.
It was both Romeo's and Juliet's idea to marry eachother.
Juliet is furious, but also feels hopeless. She then turns to Friar Lawrence and depends on him to come up with a solution for her problem
Juliet, Romeo, Tybalt, Nurse, Benvolio Or . . . Juliet, Romeo, Friar Lawrence, Nurse, Capulet Or . . . Juliet, Romeo, Friar Lawrence, Capulet, Tybalt Or . . . Juliet, Romeo, Capulet, Mercutio, Tybalt Or basically Romeo and Juliet and any three of Nurse, Friar, Capulet, Mercutio, or Tybalt.
We don't actually see this happen. What we see is Juliet promising to send a messenger to Romeo the next day at nine, then Romeo talks to the friar, then Romeo and the Nurse show up in the marketplace. Juliet may be giving her instructions to the Nurse while Romeo is talking to Friar Lawrence in Act II Scene III; it certainly happens after scene 1 and before scene 3.
to get his help in devising a plan to get out of marrying Paris .
The Nurse
Juliet's nurse.
The Friar Lawrence acts as a parental guide for Romeo, while the Nurse acts as a parental guide for Juliet. Both the Friar and the Nurse help the lovers, and they are both known more by their social roles as Friar and Nurse rather than by their actual names. Most importantly, they act as paternal and maternal influences that replace the couples' biological parents.
Friar Laurence because he can help him with Juliet, and Juliet turns to the Friar and also her Nanny
At various times, Benvolio, Mercutio, the Nurse, Friar Lawrence, Romeo's father, Friar Lawrence's friend Friar John and Romeo's servant Balthazar all try to do things which they think will help Romeo. And Juliet too, of course.