Help cleaning up years of POS data into a simple dashboard

Project Description

We're a retail hardware shop in North Delta with several years of POS exports and spreadsheets and no clear picture of what sells or who our repeat customers are. We'd like someone to clean it up and build a straightforward dashboard the owner can read without training. Not after a giant BI project, just the practical version. Google Sheets or Looker Studio is fine. Walk us through how to keep it updated ourselves.