An example of this part of the narrative arc would be in Act II when Oberon puts the potion on the eyes of the sleeping lovers and Titania.

denouement (resolution)

complicating incident

foreshadowing

falling action

An example of complicating incident would be in Act II when Oberon puts the potion on the eyes of the sleeping lovers and Titania.

Act I serves as an introduction into the play, but everything changes in Act II when Oberon does this to the sleeping lovers and Titania, because he starts the whole incident with people falling in love with wrong people. He made a mistake and thus the complications began.