My costumer was a BtoB company, and as a BtoB, is not always easy to have the full picture of who are the end users of the product. I started the project with that research in order to identify the Target Personas that would use the product.
Once the personas identified I could do a User Story Mapping to understand which were the main User Flows, and so, it's pain points. I used the Heuristic Rules to gather/identify the pain points in an ux-focused way so that I could come up with handable improvements.
After double crossing the personas User Flows I discovered which was the feature in which they all converged and which were the major problems they were experiencing (Transactions ans Search) I used a priorisation grid based in Impact vs Effort so that the backlog could be easily identified and assigned to the pertinent team. As the designer my next job was to work in a light redesign, improving the usability through easy UI fixes, and the whole UX experience of the Budget creation, as "Transactions and Search" was a too big improvement.