The question set, in order
Before: the situation
Tell me what your working week looked like before this. What was the part that caused most difficulty. Who in the team felt it most. Roughly how long had it been like that. What had you already tried. What finally made you decide to do something about it. That last question is the trigger question, and it produces the sentence most likely to make a reader recognise themselves.
Decision: how the choice was made
Who was involved in deciding. What else did you look at. What were you worried about. What would have made you say no. How long did the decision take. These questions establish that a real evaluation happened. They also surface objections that your sales team hears constantly, described in a customer voice, which is separately useful.
Implementation: what actually happened
What did the first week look like. What was harder than expected. What did you have to change in how the team works. Who resisted, and what changed their mind. Ask these directly and do not steer away from the difficulties. A case study that describes a real implementation with a real snag is believable in a way that a frictionless account is not.
After: what is different
What do you do differently now. What has stopped happening. Is there a specific example from the last month. What would you tell someone in your position a year ago. Note that only one of these asks for a measure. Ask for figures where the customer can confirm them, and be content with concrete scenes where they cannot.