How did spanish colonists acquire workers through the repartimiento system?

Repartimiento was a colonial forced labor system. It was imposed on the indigenous people of Spanish America and the Philippines. It was similar to the tribute labor systems of the Inca empire. In the repartimiento system, the natives were forced for paid and unpaid labor for a specified period of time in Spanish farms, mines, public projects, and workshops. It was different from slavery as in repartimiento the labors were not owned like slaves, they were free in many ways. But this system created slavery like conditions in silver mines of the 16 century.