It's been a while since I read this book, but I'll give the question my best shot: As a settler, Matt is largely unaware of his new surroundings until Attean, like Squanto, shows him the ways of the wilderness and nature, in particular.
As a result, Attean learns about "white man's" culture, and Matt learns how to thrive in the wild new land of North America. This book shares some commonalities with other "survival" novels like Hatchet. Matt and Attean's relationship could also be compared to that of Pocahontas and Captain John Smith, minus the romance, of course.
Matt and Attean become more and more close to each other.