I want to plant a peace lily bulb that is the only thing left from the plant that died.
How Do I Plant a Peace Lily Bulb
"Peace lilies" are not lilies; their botanical name is Spathiphyllum, and they are in the same family as philodendron. Since they are not lilies, they do not make bulbs. They have large underground stems from which the leaves and roots sprout. If what you have is this large stem, called a rhizome, you can try burying it in a pot of soil. Kept SLIGHTLY damp, it might start to regrow, but this is doubtful; If the rest of the plant has died, there is probably little life left in the rhizome. In the future, if you get another peace lily, this article will help you take care of it properly so that it doesn't die: https://www.gardeningknowhow.com/houseplants/peace-lily/peace-lily-plants.htm
If you actually have a bulb from some sort of lily plant, I'll need to know what kind it is to help you with planting it.