Link multiple flows together with annotations (scenes)
Freely move all selected elements + artboards within a work area inside the XD file work space.
Maybe group them as "Scenes" of artboards with other elements like descriptions, step sequence, title ++ that is not part of any artboards. This way you can explain the prototype within the XD file while also making it clickable as a prototype through all the artboards that is part of this "Scene" and may transition into other "Scenes" within the same XD-file.
Attached screenshot is one working area containing several artboards within the same XD file. In the XD file there is also other working areas "Scenes" like this which are explained while still maintaining it clickable as prototypes - when running in preview.
Stephan Wetaas commented
Today we can not move selected artboards and surrounding elements freely at the same time.. Quickfix is to make all comments in between as artboards, but that just feels awkward since they then will be part of preview ;-)