Yes, the manual (getting started) need update. The help file is more accurate here. But I doubt they want to fix it. I am in V.12. Is the manual for V.13 is any better?
It say:
Double-click a media file to add it to your project.
The file is added to the Project Media window, and an event is created to end of your project on the selected track.
When new media is added to the end of the project, Movie Studio automatically scrolls the timeline and zooms so you can see the new events.