Tiller provides recommended formulas for automatically populating the correct month and week dates when preparing bulk imports to paste into the Foundation Template (I’d link to them here, but I’m prohibited from including links).
I have tweaked those formulas slightly to be cleaner. Where the original formulas will continue to add dates into empty rows, the below do not. And they’re shorter, and who doesn’t like shorter formulas
Month
=arrayformula(if(row(B1:B)=1,"Month",if(B1:B<>"",date(year(B1:B),month(B1:B),1),"")))
Week
=arrayformula(if(row(B1:B)=1,"Week",if(B1:B<>"",B1:B-WEEKDAY(B1:B)+1,"")))
Enjoy