HELP!! BYU AP World History!

Read the following document then answer these two questions in the box below. First, what is the main idea of the document (not just the subject but what the author wants the audience to think about it)? Second, what are the historical situation, point of view, audience, and purpose of this document, and how does each affect your understanding of the document?

“There is, my Lord, another great obstacle to the service of God in our kingdoms. Many of our subjects greatly covet the goods which your men bring in our kingdoms from Portugal. To quench this uncontrollable thirst they kidnap many of our free or freed black subjects, even nobles, sons of noblemen and even our relatives. They sell them to the white men who are in our kingdom after having delivered their prisoners in secret or during the night in order not to be recognized. As soon as the captives are under the white men’s power they are branded. This is how they are found by our guards when they board the ships. The white men then explain that they were bought but they cannot say from whom. Yet it is our duty, as the prisoners claim, to do justice and set them free. To prevent such incidents we have decreed that all white men buying slaves in our kingdoms, however it may happen, should first inform three noblemen and officers of our court to whom I entrusted this control. ... They will check whether the slaves are not actually free men. If they are found to be slaves nothing will prevent anyone from having them and taking them aboard. However, should the opposite be true, the captives will be taken away from the white men.”
– From King Afonso to King João III, October 18, 1526, in Michael P. Johnson, ed., Reading the American Past, Vol. 1: To 1877, Boston: Beford, /St. Martin’s, 2012, p. 19.