At the moment running report to Excel will give you a report with xml-file type.
You can do 1 of 4 things:
1. Open Excel, press Open file and go to Downloads folder. Find relevant xml-file and press Open.
2. Change app settings for xml-files to always open in Excel
3. Report will be found in Downloadsfolder - change file type from .xml to .xlsx
4. In Downloads, right click on file and choose "open with" - Excel