Step-by-step explanation:
Romeo Carries Out His Plan
Romeo arrives at the Capulet family tomb to find Count Paris, whom Juliet's family wanted her to marry, already there placing flowers. Paris accuses Romeo of being there to dishonor Juliet and the Capulet name. Romeo is there illegally, forbidden to be in the city, much less on Capulet property, and Paris attempts to detain him. Romeo fights back and kills Paris. He expresses guilt over killing yet another person connected to Juliet, but he is mostly focused on his grief over the loss of Juliet.
He breaks into the tomb and, after threatening Balthasar with death if he does not leave him there to carry out his plan, throws himself on Juliet, who is still unconscious from the potion she took to mimic being dead. He has a soliloquy about lying with his wife for eternity, and rotting beside her in the tomb. Finally, he kisses Juliet and takes the poison he purchased in Mantua from the apothecary. Romeo's death is very fast, and within moments, he collapses beside Juliet.
Juliet Reacts to Finding Romeo
Friar Laurence arrives too late, immediately after Romeo dies. As Friar Laurence is agonizing over this development, Juliet awakens to find Romeo dead beside her. Friar Laurence urges her to flee with him, as the sound of Romeo's fight with Paris has attracted attention and people are coming, but she refuses.
Juliet attempts to take the rest of Romeo's poison, a few drops left at the bottom of the vial, and even poison herself by kissing him, but fails. So she takes his dagger and stabs herself.