Right, so is the data brought in from external source? Or data entry is done directly into Excel?
If former, first step is to identify all the source. Will it be from single source or multiple? If multiple source, what information/fields are available to tie data together.
For an example, is call stats fed directly into CRM for lead generation? Or are these separate system? If separate, does call stat have queue which distinguishes lead queue to existing customer queue? etc etc.
Once all these are considered, you'll then create single table or data model that collects all relevant information. Using this table/model, you'll then design visuals and KPIs that tell a story.