I added a snippet called "SiteMap" then created a blank template. Then I created a new document, set it to use the blank template and added the snippet call to the document ... but I got a error.
So I removed the snippet call from the document and added it to the blank template instead and it works.
And I just discovered that adding
[*content*] to the template and placing the snippet in the document also works.
Can I suggest you add that to the Wiki article? It’s obvious when you think (and know) about adding the [*content*] ... but when you’re following directions with pure unadulterated faith (and hope) it’s not. At least, it wasn’t to me.