Changing focus from one text field to the next in Flutter

Yes, FocusNode and the onFieldSubmitted from a TextFormField are probably the way to go.

FocusScope.of(context).requestFocus(focusNode);

Here is an example that may help:

    FocusNode textSecondFocusNode = new FocusNode();

    TextFormField textFirst = new TextFormField(
      onFieldSubmitted: (String value) {
        FocusScope.of(context).requestFocus(textSecondFocusNode);
      },
    );

    TextFormField textSecond = new TextFormField(
      focusNode: textSecondFocusNode,
    );

    // render textFirst and textSecond where you want

You may also want to trigger FocusScope.of() from a button rather than onFieldSubmitted, but hopefully the above example gives you enough context to construct an appropriate solution for your use case.