I downloaded the dmg file, and I tried to open it, a progress bar show up and disappeared.
Afterwards I found the etcher file in the device section, so I tried to open it and it says “balenaEtcher 1.5.15” can’t be opened because the original item can’t be found."
You should be able to get Etcher from https://www.balena.io/etcher/ .
Click on the “Download for macOS” button.
Open the downloaded dmg file, drag and drop the “balenaEtcher” icon onto “Applications”.
A “balenaEtcher” icon should appear in your dock.