Open with the situation in two or three sentences: who (anonymised, e.g. "a mid-sized logistics company"), what they struggled with, and why it mattered.
The problem
What was going wrong or missing? Use their words if you can.
What we did
The approach, the key decisions and why. A simple architecture sketch in words or a list works well here.
The result
What changed. Use real, approved numbers only; otherwise describe the qualitative outcome.
What we learned
One or two lessons another team could use.