If you want to display a text across multiple images, create a track with a Text object in a Chapter object. First insert a Chapter object and drag your images or videos into the Chapter object.

Below the inserted images or videos, there is now a narrow line with the label "Drag here to create new track". Now drag a text object to this position.

In the Propertieswindow,  you will see a text input field in which you can enter your text. You can also influence the design of the text there.

To extend the display duration of the text object, you can either extend the display duration in the Properties window under Duration. You can also shorten or lengthen the display duration via Timeline. To do this, move the mouse arrow to the edge of the Text object. Drag or move the mouse along the edge of the Text object while holding down the mouse button.

If you want the text to appear later and not at the same time as the first image, place the text object in the second track with a slight offset.

You can find out about other options for captioning video objects in the "Labeling videos" chapter.