​
Pages

If you don’t want any hierarchy, you can just define pages within your navigation field. Each entry of the pages array must be a path to a file that exists within your repo. Note you do not need to append .mdx to the file paths. 
{
  "navigation": {
    "pages": [
      "overview",
      "quickstart",
      "advanced/components",
      "advanced/integrations"
    ]
  }
}

​
Groups

Groups allow you to group your pages. Groups can also be nested within each other. 
{
  "navigation": {
    "groups": [
      {
        "group": "Getting Started",
        "pages": [
          "quickstart",
          {
            "group": "Editing",
            "icon": "pen-paintbrush",
            "pages": ["development", "web-editor"]
          }
        ]
      },
      {
        "group": "Writing Content",
        "pages": ["writing-content/page", "writing-content/text"]
      }
    ]
  }
}