First, create a Duda Tabs widget on Common Ninja.
On the widgets catalog, find the Tabs and enter the Editor.
When you're done creating the Tabs widget, click on the Save Changes button at the right top corner of the editor.
If you don't have an account on Common Ninja, you'll have to register first.
When you're ready to add the Tabs widget to your Duda website, click the Add To Website button at the top bar of the Editor.
On the window that opens, click the Copy Icon to copy the widget embed code. In the next steps, you will paste this code into your Duda website.
Now, let's head to the Duda's website editor.
On the Left panel, enter Widgets.
Find and select the HTML widget.
Drag and place the HTML widget wherever you wish the Tabs to show.
Now, delete the code in the HTML Content window on the left panel and simply paste the Tabs embed code you've copied before.
Click the Update button on the bottom of the HTML Content window to save your change.
Please note: you might need to refresh the page to see the Tabs content in the editor (wait until the editor auto saves your changes).