Blessed Are the MercifulFor they shall obtain mercy
Once, as I was going down the hall to the kitchen, I heard these words in my soul: Say unceasingly the chaplet that I have taught you. Whoever will recite it will receive great mercy at the hour of death. Priests will recommend it to sinners as their last hope of salvation. Even if there were a sinner most hardened, if he were to recite this chaplet only once, he would receive grace from My infinite mercy. I desire to grant unimaginable graces to those souls who trust in My Mercy.
Here is a site that tells how to recite the chaplet: https://www.thedivinemercy.org/message/devotions/pray-the-chaplet