The first encounter Matt and Attean have occurs when Matt is injured attempting to retrieve honey from a beehive. Since Matt has fallen out of a tree, he is partially unaware of who has rescued him at the time, so this might not qualify as a meeting.
A short time later, the two do officially meet when Attean and his grandfather, Saknis, return to Matt's cabin where they had taken him. Saknis brings Matt food and cares for his bee stings and injury from the fall out of the tree. Attean accompanies Saknis to the cabin. When Matt tries to give them a book, one of his few possessions, in return for the care they give him, Matt realizes they cannot read English. Saknis reveals that he wants Matt to teach Attean English. It is at that time that Matt and Attean meet on a deeper level and get to know each other better.