Optional Opening Prayer:

You expired, Jesus, but the source of life gushed forth for souls, and the ocean of mercy opened up for the whole world. O Fount of Life, unfathomable Divine Mercy, envelop the whole world and empty Yourself out upon us.

(Repeat three times)
O Blood and Water, which gushed forth from the Heart of Jesus as a fountain of Mercy for us, I trust in You!

To pray the chaplet:

Using regular Rosary beads, begin with the Our Father, Hail Mary, and Apostles' Creed.
On the large or 'Our Father' beads pray:

Eternal Father, I offer you the Body and Blood, Soul and Divinity of Your dearly beloved Son, Our Lord Jesus Christ in atonement for our sins and those of the whole world.

On the small or 'Hail Mary' beads pray:

For the sake of His sorrowful Passion, have mercy on us and on the whole world.

Continue through the 5 decades and then conclude by praying three times:

Holy God, Holy Mighty One, Holy Immortal One, have mercy on us and on the whole world.

Amen

Optional Closing Prayer:

Eternal God, in whom mercy is endless and the treasury of compassion — inexhaustible, look kindly upon us and increase Your mercy in us, that in difficult moments we might not despair nor become despondent, but with great confidence submit ourselves to Your holy will, which is Love and Mercy itself.