hi
You are correct.
what is supposed to happen, before you download it, is decide how the extension is to be ....in terms of persistence
assuming you are doing a clean install.from the live cd...I suggest you pulldown the bottom menu and select
download and install to access it.
Then do the same for your preferred bootloader.
2) once you reboot with a bootcode using some kind of persistence, assuming that you prefer some form of persistence, other options of
onboot or ondemand then become logically available.
So yes the dox need improving......maybe the 2x and 3x way of doing things needs culling and only the newer 3.1 way becomes the new document....but I will leave that to the mods.
regards