Thanks. I have made some progress and can now do most of what I wanted to do. The main thing I am stuck on is how to use a document that already exists , already has merged fields placed in it, and run again from the same excel file (with same field names).

For example, if I have a document that looks like

had a little whose fleece was white as .


and I added merge fields as indicated below

«First_Name» had a little «Animal» whose fleece was white as «Substance»


After I have run this mail merge and a week later want to run it again, how can I use it without having to again select the merge fields? If I pull up the document used a week ago, it seems to populate from the previously completed merge, I want to run the same mail merge with same fields but updated contents from the excel sheet.