hi Steven, merci for the response

The FormatDateTime() is a hidden function that formats dates (and times). Although hidden I use is daily to show human friendly results fitting my region (Europe, Belgium)

_allDatesThisMonth is a named function I created to get a list of actual dates. I had to write this function so often that I decided to write a function on the canvas and to name it so I could reuse the outcome in various places. This logic also helps to keep your doc fast (one calculation instead of many).

ahah, you found the Dates123 in screenshot on generating weeks. This is indeed a reference to normal dates but the column is a number value and not a date value, but I can distract properties like isoweekNumber from it

hope it helps. Cheers, Christiaan