So, you must follow the instructions for sites that use custom page templates. The process I've followed

  • log into BigCommerce and create a new page. In this case, the page is "/newsletter/"
  • Create .stencil and add it to the customLayouts -> page list (see below)
  • Create and edit [sitehome]/templates/pages/custom/page/newsletter.html
  • View the page locally and verify that it appears as expected.
  • Perform a stencil push.
{
  "customLayouts": {
    "brand": {},
    "category": {},
    "page": {
      "locations.html":"/our-stores/",
      "employment.html":"/employment/",
      "newsletter.html":"/newsletter/",
      "ask-beth.html":"/ask-beth/"
    },
    "product": {}
  },
  "apiHost": "https://api.bigcommerce.com",
  "normalStoreUrl": "https://www.samdoit.com",
  "port": 3000,
  "clientId": "xxxxxxxxxxxxxxxxx",
  "accessToken": "xxxxxxxxxxxxxxxxxx"
}