How to implement edit functionality in ThymeLeaf in Spring MVC

I am using this tutorial I see delete functionality for each row:

7.6 Dynamic fields

Thanks to the advanced form-field binding capabilities in Spring MVC, we can use complex Spring EL expressions to bind dynamic form fields to our form-backing bean. This will allow us to create new Row objects in our SeedStarter bean, and to add those rows’ fields to our form at user request.

In order to do this, we will need a couple of new mapped methods in our controller, which will add or remove a row from our SeedStarter depending on the existence of specific request parameters:

@RequestMapping(value="/seedstartermng", params={"addRow"})
public String addRow(final SeedStarter seedStarter, final BindingResult bindingResult) {
    seedStarter.getRows().add(new Row());
    return "seedstartermng";
}

@RequestMapping(value="/seedstartermng", params={"removeRow"})
public String removeRow(
        final SeedStarter seedStarter, final BindingResult bindingResult, 
        final HttpServletRequest req) {
    final Integer rowId = Integer.valueOf(req.getParameter("removeRow"));
    seedStarter.getRows().remove(rowId.intValue());
    return "seedstartermng";
}

And now we can add a dynamic table to our form:

<table>
  <thead>
    <tr>
      <th th:text="#{seedstarter.rows.head.rownum}">Row</th>
      <th th:text="#{seedstarter.rows.head.variety}">Variety</th>
      <th th:text="#{seedstarter.rows.head.seedsPerCell}">Seeds per cell</th>
      <th>
        <button type="submit" name="addRow" th:text="#{seedstarter.row.add}">Add row</button>
      </th>
    </tr>
  </thead>
  <tbody>
    <tr th:each="row,rowStat : *{rows}">
      <td th:text="${rowStat.count}">1</td>
      <td>
        <select th:field="*{rows[__${rowStat.index}__].variety}">
          <option th:each="var : ${allVarieties}" 
                  th:value="${var.id}" 
                  th:text="${var.name}">Thymus Thymi</option>
        </select>
      </td>
      <td>
        <input type="text" th:field="*{rows[__${rowStat.index}__].seedsPerCell}" />
      </td>
      <td>
        <button type="submit" name="removeRow" 
                th:value="${rowStat.index}" th:text="#{seedstarter.row.remove}">Remove row</button>
      </td>
    </tr>
  </tbody>
</table>

Quite a lot of things to see here, but not much we should not understand by now… except for one strange thing:

Now I won't implement edit functionality.

Ideas?