I have just (painfully) upgraded to Ubuntu 18.04 LTS. Since it appears I have no choice but to use the GNOME desktop, I am trying to make adjustments so that I can use it more like the Unity desktop I used in 14.04 and 16.40. But I find I can make no changes to the size and position of the Dock.

When I go to Settings and click on Dock, the only thing visible in the large right-hand panel is a very faint slider bar, with no slider. Positioning the cursor over this bar has no impact. In short, on my system the Dock is completely unadjustable.

What I was expecting was something like this: https://websiteforstudents.com/resize-and-adjust-ubuntu-dock-on-ubuntu-18-04-lts-beta-desktop/. I.e., the ability to adjust the size, position and auto-hiding capability of the Dock.

What do I have to do to make the Dock adjustable?

$ apt-cache policy gnome-shell-extension-ubuntu-dock
 Installed: (none)
 Candidate: 0.9.1ubuntu18.04.1
 Version table:
   0.9.1ubuntu18.04.1 990
     990 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
     990 http://us.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages
    0.9.1 990
     990 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
     990 http://us.archive.ubuntu.com/ubuntu bionic/main i386 Packages