The translation of content is done by actually creating a copy of the default language and then replacing the text with the translation. All images and other settings of the default element are copied.
To create the copy click on the button with the text "Copy default content elements". (img. 3.1.1)
A copy will appear in the language column. Edit the content to replace with correct language, by using the pen icon of the element or by clicking on the text of the element. (img. 3.1.2)
The new copied element is hidden automatically. If you want to publish it, go to the Access-tab and uncheck the Disable box (img. 3.1.3). Below each field the default text is shown with a green background. If any changes has been made to the default element, added text will appear in green and deleted text will appear in red (img. 3.1.4).