There’s a potential ambiguity in the current discussion that might be causing some confusion. When you wrote “template that I clicked on”, where did you click on the template? Was it in the macOS Finder?
Based on the screenshots posted above, I think you may be trying to click on DEVONthink’s templates in the macOS Finder. What Jim is trying to explain is that this won’t work for DEVONthink’s templates. Instead of trying to click on the template file in the Finder, create a new note by using the DEVONthink menu item that Jim wrote about:
The files that are added to the template folder on disk will show up in DEVONthink’s menu there.