First, write down the problem statement so that you as the author of the story is very clear about problem context, the stakeholders who are impacted, what the impacts are and what might the ideal solution looks like in some time frame into the future.
2. Capture the problem statements as a result of interview in the previous step.
3. Verify the problem statements
4. Translate one problem statement to one or more user stories.
5. Validate those user stories with stakeholders
6. Repeat step #1 until all problem statements from all affected stakeholders have been documented.