You might have to get a Module to handle .xlsx files. Ignition handles CSV files out of the box, but I don’t believe it handles .xlsx files.
So your choices are get a module like http://www.perfectabstractions.com/pa-office-document-module.html and then go through each for of the excel file, inserting it into the database one row at a time with a query you wrote.
Or turn your excel files into .csv files.