Shakespeare plays tend to have five acts, and the five acts follow the plot diagram. The first act is the exposition. In this act, we are introduced to the characters, the setting, and the basic problem. In this case, that means we learn about the feud and Romeo and Juliet.
Then in the second act, Shakespeare introduces complications. Romeo and Juliet's love blossoms in Act 2. They decide to get married despite their parents’ concerns.
O, swear not by the moon, the inconstant moon,
That monthly changes in her circled orb,
Lest that thy love prove likewise variable.(Act 2, Scene 2)
In Act 3, the climax will occur. The climax is the turning point. In this case, Romeo gets Juliet's agreement to marry, but then Tybalt kills Mercutio and Romeo fights back in anger, killing him. As a result he is banished. At the same time, Juliet’s parents decide she should marry Paris. This is the turning point because nothing can stay the same. Romeo and Juliet can’t just marry now. They have to make a plan.
Act 4 is the plan. This is the falling action, or the outcome of the climax. Romeo and Juliet do marry, but they only get to spend one night together. Juliet fakes her death so she does not need to marry Paris.
Act 5 is the resolution. It solves the original problem and the new one introduced by the climax. In this case, Romeo finds Juliet dead (he thinks) and kills himself. She wakes up and finds him dead (for real) and kills herself (for real). The parents decide they are done with their feud now that their kids are dead.