Is it correct to assume you’re trying to use the Excel-like Handson table? If so, (to my knowledge) it cannot be used for displaying the content of an uploaded Excel/CSV file.
Rather, it needs to be data that already exists in your database (or that you retrieve from an API). (As well, the Handson table is built for record-based data. So, if your document is a calculator, it’s a double no go).
If you’re looking for some creative solutions for file previews, @ryan8 shared some here: How to show a file.