what do you do when Not Enough Information on the Story code example

Example: what do you do when Not Enough Information on the Story

2. Not Enough Information on the Story
There was a times when our product owner
who writes user stories, has some idea
about a new feature but doesn’t have all
the details to write a good set of acceptance criteria
to fully define the behavior of the feature.
She was askin the development team to create a 
prototype so we can get more ideas about the
functionality and behavior of the feature.
This was creating a challenge to me as a tester
because there was a lack of understanding and requirements,
so I wasn't able to construct proper test cases.

Solution:
So what I did was as a Tester I had to depend on my
judgement in this case. I din’t need very detailed
requirements to start testing, so I start by thinking
about high level scenarios that test the concept of the story
, rather than waiting to get full clarification about the
feature and losing time. By drafting high level test scenarios,
even when the details change, the context should
still be the same. When test cases are written
on the basis of high-level use cases, changes
in feature details will result in minor variations
in test scripts. This is because the context and the
wider user journey remains the same. So instead of 
waiting for PO to give me full description and losing time,
I start working on creating tests.