Hi there
here is the link to @Melissa Calendar posting
Extended Date Table (Power Query M function) - Power Query / M Code Showcase - Enterprise DNA Forum
Just copy the m code into a blank query
Within the EDNA Dashboard there is a Lab that was setup that fully explains it.
Lab
Dashboard (enterprisedna.co)
there is also a video on it
Dashboard (enterprisedna.co)
I hope this helps.
Keith