Very nice challenge - my result differ from initial as I've run it 2 days later - I have 8 rows more but totals are in line :)
Oh and on a side note there seems to be mistake in description of the excercise - starting date is written as 2018 while in the solution it is 2017.
ManuelTsang. I'm not sure exactly where your troubles are occurring but I use the Chrome browser and click the "Choose Files" button > browse to file > open. Wait for the file to upload (the arrow icon will turn into a hand when hovering over the "Post" button). I have attached a screenshot.