UPDATE - SOLUTION
On Windows 10 I have now found a way to make it work. If one goes to the template page (https://www.evernote.com/templates) and you select a template - it DOES add it to your template library if you are logged into Evernote in a separate window on the same browser. It is massively confusing because the template page asks to SIGN UP or LOG IN - and if you do so - you immediately lose that page. I can't find any sequence or solution to showing it LOGGED IN - but it doesn't seem to matter.
When you then go to add a NEW NOTE (in Evernote Windows) There is a small icon labeled TEMPLATE in the body that allows you to select from those you added on the template page.
At Evernote.com however the OLD evernote does not give you this option. You must go to YOUR ACCOUNT on the bottom left of the Evernote.com page, and select (something similar to) TRY NEW EVERNOTE WEB LAYOUT). This will take about 10-15 seconds to load and when you add a new note - it also has the templates you have selected.