Columbus' goal was to establish permanent colonies in the New World that he would govern. The main purpose of these settlements was to convert all the natives to Christianity.
In terms of how Columbus saw the Native Americans as part of a Spanish Colonial Empire, he saw them as laborers and cultivators for cash crops. He eventually became governor of Hispaniola (the island where Haiti and the Dominican Republic are now). He was known for forcing the native Arawak and Taino tribes to undergo so much pain and hardship in digging mines and cultivating cash crops that numerous natives died. Spanish officials actually wrote to Spanish Monarchy to revoke his position on account of these egregious abuses. Eventually, they were heeded and Columbus was deported back to Spain.