I'm the Product Owner on a project, which is essentially the integration of a new technology into an existing product. A prototype has been written by an external developer and we are now tasked with integrating these changes into our code-base.
From what I understand from our, this is mainly about doing a large code-review and making sure that the code is in good enough shape for production.They estimate this work to take in the region of three-months and has many dependencies on other projects. The work hasn't been broken down to a level or form that can be expressed as user stories.
How can I best break this down into user stories with a value that I can express to the business and ensure that the product ultimately delivers value to the end-customer?