Start with one complete request
Example: entry → attachment → review → approval or return → lookup. The first version should complete that workflow, including correcting a mistake. You do not need to migrate the entire business to test it.
The test before replacing Excel
Use an authorized sample and ask the team to complete a request. Check who can view, correct and approve it. Define data export and what happens when the system is unavailable.
Your checklist
Check what happens today. This is not an automatic score: prioritize the issue with the greatest effect on your team.