Install from Deb

[Grizzly]

Hi All

Not sure what I'm doing wrong, I wanted to "try" the Vivaldi Browser,

updated & full-uprade 

then I downloaded (save file)

https://downloads.vivaldi.com/stable/vivaldi-stable_3.7.2218.52-1_amd64.deb

select saved file, choose software install as the action

After a few moments got a dialogue "not supported"

I usually go the apt install route so I'm not sure what I did wrong?