How did the Pilgrims become friends with the Wampanoag?
The Pilgrims numbered only 50 souls, the other 50 were either the ship's crew or people enticed to come because of their particular skill being needed in starting a colony.
The Mayflower left about 100 people at the Plymouth Colony in October 1620, By April of 1621 almost half had died, starvation being either a direct or indirect cause of death.
The Pilgrims recognized the necessity of befriending the "locals" to help them become a viable colony. The Wampanoag obliged by showing them what to fish for, how to plant and cultivate crops in the rocky Massachusetts soil, and how to hunt in the woods.
The harvest of 1621 was quite successful and they gather and gave thanks, including the Wampanoag in their festivities. The first Thanksgiving happened.