Hmmm, ok. That guide you’ve found is only for the text standard widget, not the other custom widgets etc. That literally will allow a string translation for what ever is in the text widget only.

When you run the Po/Pot file – , where it says to include the 10 widgets, do the strings for the widget then appear in the Po/Mo files?

What you could do, is add multiple copies of the widget, one for each language and then use Widget Logic to turn the widget on/off depending on what language the page is displayed in as per –