Determining a test plan at the story-level

I have been asked to start creating test plans at the story level and I'm rather confused about how to do this efficiently. In my experience, test plans have been high-level documents that were written at the epic level and didn't descend into the specifics around individual stories. I don't want to spend so much time and effort on a high-level document (which I've never had to write before either) if that isn't appropriate.

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So, can anyone give me some advice or examples of how this should go at the story level? Or direct me to any resources online? I've been googling but haven't quite found what I'm looking for yet. Thanks reddit!