Reyware apt setup (Ubuntu, Debian etc)

in a terminal window as root...
1 add the gpg key (the hyphens by themselves are important)
wget -q -O - | apt-key add -
2 with your browser, download the package for your cpu here
3 open the browser's downloads window, or your Downloads directory
4 right click the .deb file and choose 'Open with GDebi package installer' or something similar
or, staying with the terminal window as root...
cd Downloads     (or whereever your browser saved the deb file)
dpkg -i amb-ux_1.14.6-1_amd64.deb    (or whatever the deb file you downloaded)