Where to start?

It happens that every so often a student presents a written assignment that is so far off base I don't have a clue where to start with it. I am not always sure if it is because the teachers instructions were not clear, if the student just didn't understand them or if they just didn't bother to read them. Sometimes, it is a combination. In a recent one, the teacher instructed that a student should state their purpose and main points. (They did not mention the term thesis). The teacher did mention that the student should have a conclusion and references cited and that pages should be numbered(but no thing on required length) So was the teacher assuming the student understood the correct format or were they lenient as to how the paper should be set up?

Regardless, as a result, the paper I received had no clear thesis, no topic sentences, unconnected points, and was a single page in length.

The students requested that I check the flow,...in my opinion, there was none. It read like a dry snippet of facts that were vaguely related.

I tried to get in a discussion of thesis but quickly lost them, so opted for the teacher's....What is the main purpose of the paper? .

I attempted to go over structure stressing the importance of topic sentences but lost them when trying to explain they needed to draw a connection between their main points and supportive material.

I guess I'm pretty lost myself in as how I should have approached this one?