Anyway, after some intense googling I did manage to find the page with the scenarios again! It's here for anyone who happens to be interested:
http://syw-cwg.narod.ru/HM_scnE.html

I remember seeing on this forum, or a related forum, last year containing links to downloads for custom scenarios for Horse and Musket: Great Battles of the 18th Century (the one from 2001, not the 2010 one).

There were several for battles from the Kościuszko Uprising, and others from the Russo ...

It works now! Thanks! Look like I was changing numbers where they shouldn't have been changed. I though that "Unitcount" would need to match the numbers below it, and so I changed it to a 2. Seems that the ScenarioDesign PDF isn't completely accurate.

Now I can play Minden as the allies. The French ...

It looks like you have a couple of .BAM files in the scenario folder. You have to leave only one with your changes. I have done all actions mentioned by you and me and voila
https://i.imgur.com/2vr7uKY.jpg
I can play Minden for the Allied side. Of course, it would be better to script AI in a new ...

I switched the unitcount numbers, and now I get two error messages when I try to load the scenario and the program crashes. One of them says something like “moving unit into occupied tile.” I can screenshot them for you. It looks like to get the scenario to load, each section containing a “_0_”, “_1 ...

Has anyone successfully converted a scenario so that one could play it from the originally non-player side? I would like to be able to play Odenthus' Minden scenario from the Allied side against a French AI. I attempted the "switch sides" method from the ScenarioDesign PDF which is:

"Open a copy ...