I switched over to Gutenberg, now the duplicate button does appear.
However, since it wasn′t clear how to use this/duplicate, here are the steps for everyone else:
- Make sure you are using Gutenberg to create new posts/pages.
- Create new post/page, add title and content.
- Save/publish.
- Go back to the editing of the post/page, find the Translations section.
- Click the + button next to the language version you now want to create of this page.
- A new empty post/page will open in edit mode.
- Go to the Translation section, look for a button “Duplicate translation from (previous language)”.
- Click = Duplicate.
- The currently opened page will now be replaced by a new one that will import the title and the content from the post/page language you selected.
- Be carefull that the words “translation” will be automatically be added to the title; delete/edit title/page as you wish.
- Save/publish.
- Repeat for more languages if needed.
It would be great if the developers copied these “how to” into the instructions section.