Use the following instructions:
Install the repository in one of the following ways:
Install the getdeb package.
Or configure the repository manually:
Go to System-Administration-Software Sources, Third-Party Software tab, Add:
deb
http://archive.getdeb.net/ubuntu xenial-getdeb apps
Add the repository GPG key, open a terminal window and type:
wget -q -O-
http://archive.getdeb.net/getdeb-archive.key | sudo apt-key add -
Click the "Install this now" button below the screenshot of the desired application.
If you are using Kubuntu please check bug 476853.
If the application cannot be found, run this command and try again:
sudo apt-get update
If you want to uninstall the GetDeb repository run this command:
sudo apt-get remove getdeb-repository
If you get a blank page when installing you need to configure apturl in your browser.
In Firefox you need to change the setting also in Preferences->Applications
Link the apt protocol to /usr/bin/apturl there.