How do you steal shadows?

Obeah, Obi, Obea or Obia men were once believed to have the power to steal shadows.

They are a part of a cluster of religions from the West Indies that started in West Africa. (Ashanti and Koromantin tribes). It was a common religion of the slaves that were brought to Europe and the Americas.

Jamaica, Trinidad, Guyana, Barbados, Belize and other Caribbean countries have active Obeah-Men.

Forms of this practice is Vodun, Voodoo, Santeria, Palo, and other forms of similar magick or witchcraft.

Often "Stealing of shadows" was a way of saying to curse or to hex someone...

So I guess the best answer would be to become a part of that type of religion to learn these types of rituals.