This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
The 'slider' element¶
The image slider starts with the same 'general' and 'frame' palettes. Next it will get a bit more challenging.
The editor can add images and links to the element, but they need to be able to include as many images as they want.
This feature is well known from TemplaVoilà and with a bit of effort it can be done with just core functionality.