I just downloaded LibreOffice for the first time. I downloaded version 188.8.131.52 (x86).
I want to add a bookmark to a PDF document. I was able to do so with Adobe Acrobat.
I found instructions at Insert Bookmark - LibreOffice Help about the menu, Insert, and Bookmark command. I also found a good video about the command,
I started the program for the first time. I see LibreOffice Writer in the title bar. I saw that in the video.
I opened the PDF document. In the title bar LibreOffice Writer turned to LibreOffice Draw.
I opened the insert menu. The insert menu did not have a bookmark command.
Also, in the video, a star navigation command appeared on the tool bar. I do not see that command.