Uh I don’t think the C in Ceiling should be capitalized
A prepositional phrase starts with a preposition. Given that the preposition in this sentence is the word <em>in, </em>the prepositional phrase is in the contest. The word it modifies is paint.
Where does Devon want to paint pumpkins? In the contest.
If you need help writing this (the document won't load) but pick out your introduction paragraph, then pick 1 quote for how ever many paragraphs you need (besides introduction and closing) then summarize in the closing!