Installing the Ubuntu Unity desktop launcher
I run Thunar for my file manager. Presumably this will also work with Nautilus. In your file manager, navigate to /opt/darktable/share/appdata. Double click (execute) darktable.appdata.xml. It’s a desktop component. It will execute darktable and the shortcut for the running application will appear in the launcher, where you can right click it and lock it there.
Installing the soft links
In order to make DarkTable behave just like the Ubuntu package, with command line options and man pages, you can add some (optional) soft links that will make the app available even though it’s not in the user’s path. This makes upgrades easy. All you need to do is delete the old /opt/darktable directory and run the build and install scripts, the same way you did it the first time. The soft links and the launcher will still be there and everything will work with no changes. We’re going to change one of the configuration files in a little while though. If your camera’s noise profile isn’t included in the new release yet, you’ll still need to add it manually, after upgrading. It’s the same procedure described below, so I’m not going to go into it just now.
See the list of optional soft link commands.