New Properties and templater prompts and commands?

I have read this a few times and obviously am missing things. I get the basic functionality ( replacing and adding frontmatter in existing file) working, but the rest of my content ( other headings etc…) are somehow replaced when the script starts running. Any idea why? My basic operation is cmd n - for a new note, followed by a shortcut key for the Templater script. Any direction would be highly appreciated.