Cannot find examples of sever-side grouping, usage of manualGroupBy option

[roblatprogen]

I did quite a few searching over Internet, cannot find examples for server-side grouping, i.e. table data is already grouped as result returning to frontend.
For example, server side returns:

[
  {
    name: "1st school",
    classes: [
      {
        name: "1st class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
      {
        name: "2nd class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
      {
        name: "3rd class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
    ],
  },
  {
    name: "2nd school",
    classes: [
      {
        name: "1st class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
      {
        name: "2nd class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
      {
        name: "3rd class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
    ],
  },
  {
    name: "3rd school",
    classes: [
      {
        name: "1st class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
      {
        name: "2nd class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
      {
        name: "3rd class",
        students: [
          { name: "1st student" },
          { name: "2nd student" },
          { name: "3rd student" },
        ],
      },
    ],
  },
];

I found some information at: https://react-table.tanstack.com/docs/api/useGroupBy about manualGroupBy.
Looks like this option should be used for server-side grouping.
However, I still have questions like:

• should I rename those sub rows field name to 'subRows'
• should I pass field names to groupBy paramter.
• how to define columns for the table and render a flat columns for the table
• how to render nested rows
  Maybe I can figure out the answers myself in Codepen.
  However, it would be great there could be some "official" examples, which can be useful for other future react-table users.