Dear Wolfgang,Thank you very much. This is very helpful.One note is that to center the footer required\setupletterframe[foot][align=middle]
(1) is there a more efficient way to indent only the content of the letter:
\setupindenting[yes,small]\setuplettersection[opening][indenting=no]\setuplettersection[subject][indenting=no]\setuplettersection[closing][indenting=no]\setuplettersection[signature][indenting=no]
(2) The following did not properly left-justify the date (the date was towards the left but was not perfectly aligned with the other left-justified text):\setupletterlayer[reference][alternative=e]