Attribution is a way of saying who or what is responsible for something. Let me give you an example.
Say you went to the park, and had a really fun time playing on all the slides and swings. When you get home, your mom might ask you who made the park and why you had so much fun there.
The answer is attribution! The people who made the park would be responsible for giving you the fun experience. Your mom is asking you to attribute, or to say who made the park and why it was so much fun.