Hi there, I have an assignment where I'm asked to analyse the following 3-line paragraph, identifying all the adverbial elements within it, and give a reasonable explanation according to the relation of these elements to the rest of the clause, sentence or paragraph:


For several minutes after his address Mr. Obama greeted audience members. Then he returned to the White House, where a huge red ribbon hung from the North Portico in honor of World AIDS Day, flanked by two newly decorated Christmas trees.


Could you explain me how these elements I signaled in bold, are acting as adverbials, and show me how I coud explain it in a single paragraph?

Thanks in advance!