Gutenberg

1.) Click on the plus sign on the top-left of the page...


2.) Type Flexmls into the search bar...

3.) Click on the widget you wish to apply to the page OR you can click and drag it onto the page.
After the widget is applied to the page, you should see the widget settings in the right-column.
If you do not see the widget settings click on the Setting button on the top-right -

You can also find the Gutenberg editor in the middle of the page: