A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Yes and yes.
Follow the steps in the video, all data from all files is condensed into one sheet. Or in your version you can load it into a data model and use Power Pivot .-)
At the end of the video he shows that new data (and/or new sheet and/or new files) are also added automatically.
Power Query is a very powerful tool, it is no more complicated than Excel itself. Imagine you are opening Excel for the first time. After a short familiarization period, it quickly becomes easy to select the appropriate commands with the UI.
Don't look close to the generated M-Code, that's for advanced users.
Andreas.