In this video I show you how to install the latest development version of darktable. If you’d like to try out the latest and greatest features (and don’t mind things being in a state of flux), check this video out. It might be easier than you think.
Warning: this can break your database (which contains your styles and tag collections). Back up your database (usually in ~/.config/darktable) before trying out the development version.
It’s also worth checking out the instructions on the darktable website.
If you installed in the default location (/opt/darktable) here’s a link to a modified .desktop file to add an icon to Ubuntu’s Unity launcher (copy into ~/.local/share/applications and then search for darktable in the Dash).