to bother everyone with a very simple question, but I've been trying for
without success

I know how to refer to a specific range like this:

For Each c In ActiveSheet.Range("d2:e14").Cells
c.Value = "Don"
Next

I can refer to a currentRegion too

For Each c In ActiveCell.CurrentRegion.Cells
c.Value = "Don"
Next

What I can't seem to do is apply this to a range of cells selected by the
user

I've tried different variations of ActiveWindow.RangeSelection.Address but
have failed

something like...
set myrange=ActiveWindow.RangeSelection.Address
For Each c In ActiveSheet.Range(myrange).Cells
c.Value = "Don"
Next

My sincerest apology to bother everyone for what should seem like a trivial
task