It's #mailmerge time again. Time to curse at my Mac.
I gave up on Numbers/Pages a few years ago and moved over to Excel/Word which I think does have more controls.
This video did help:
https://www.youtube.com/watch?v=O9IOY7-BKdE
This time it created a document that had 3 pages and my printer ignored the print only the first page ¯\_(ツ)_/¯ it's never done that - and I didn't realize double sided was on. It took like 6 tries to get 2 pages printed. Eventually I deleted everything except the remaining page.😖