Signing Up for Homework Help in My Camp Instructor's Classroom

The view of Eric's classroom from the back of the room, where the ETAs usually sit during observation

THE HOMEWORK HELP REQUIREMENT
We are required to participate in at least one "Homework Help" time during Camp Fulbright. I signed up to help out in my CI's class a day after I gave my lesson on "The Interpretation of Dreams" to have more time with the students and to get to know them better, especially since my second time teaching would also be in the same classroom, with the same students. Many of them remembered me as the teacher who gave the lesson on "interpretation of dreams."

In an email, Eric said that his students usually spend homework time catching up on assignments they hadn't finished from earlier on in the day or week. He said that, since the assignments were writing-based and require them to produce "polished" paragraphs summarizing articles and making up fictional stories, we could help by chatting with the students about these writing pieces. He warned us that they are self-motivated enough to sit in isolation and complete everything on their own, and that we might be bored because of this.

THE CHALLENGE OF PRODUCING ORIGINAL CONTENT
I went anyway and accomplished what I set out to do: talk each student individually and gauge their speaking and writing abilities by peaking over their shoulders as they wrote and, later, asking them questions about their content. The boys finished first, but it appeared that they had merely copied a few significant sentences from their assigned articles and stitched them together as their own "summary." I tried to explain that this was plagiarism, but the concept of plagiarizing seemed foreign to them.

I was forewarned about this during our teaching workshops! I will have a couple more weeks to figure out how to deal with this should it arise in my own classroom.

The girls worked slower but appeared to produce more original content as far as summarizing their articles.

ERIC'S CREATIVE WRITING ASSIGNMENT
Eric had given each of them a picture isolated from the news articles they came from. Their task was to observe the picture and, based on what was going on in them, write a fictional story. Later, they would receive the news articles that the pictures originally came with and see how "close" their fictional stories were to the actual news stories.

Eric: This is to give them a creative writing exercise. [In general, Korean students do a lot of memorization and do not have as much opportunity to exercise their imaginations].
Me: Wow, this is such a cool activity!
Eric: ...No, not really. 
Me: ...what?! I think it is. I would have never thought of something like this.
Eric: No, believe me, it's not that creative. You could easily come up with something better. 

He waved me off and instructed me do whatever I wanted in the classroom: study for my own classes, sit and chillax in a corner, or talk to the students. Seeing that I was unwilling to sit and chillax in a corner, he gave me the task of giving the students the articles after they were done writing their fictional stories. It was a small task, but there really wasn't much he needed help with.

MY QUESTIONS FOR YOU
How would you go about explaining the concept of "plagiarism" to a young student? If you were giving a writing assignment, how would you ensure that the students create their own content instead of merely plucking a few sentences from the text they're working with? Any ideas would be welcome! Please share them in the comment box below.