Install Tor Browser
Set a keyboard shortcut to start Tor Browser
Remember the location where you downloaded the tor-browser-linux64-xx.x.xx_xx-xx.tar.xz archive. In this example I will call this location /home/your-username/Downloads/
which is the default location of the Downloads directory in Ubuntu if you replace your-username
by your own user name.
Remember the directory where you extracted the Tor Browser files. In this example I will call this directory /home/your-username/Downloads/tor-browser_en-US/
where en is the abbreviation for the language and US is the abbreviation for the nation which could be different depending on your language and nation.
Go to Settings -> Keyboard -> View and Customize Shortcuts -> Set Custom Shortcut.
In the field after Name type Tor Browser.
In the field after Command type:
sh -c '"/home/your-username/Downloads/tor-browser_en-US/Browser/start-tor-browser" --detach || ([ ! -x "/home/your-username/Downloads/tor-browser_en-US/Browser/start-tor-browser" ] && "$(dirname "$*")"/Browser/start-tor-browser --detach)' dummy %k
In order to fill in an entry in the field after Shortcut press any easy to remember keyboard shortcut combination (e.g. Ctrl + Alt +B).
Now you can start Tor Browser by pressing Ctrl + Alt +B.