A .deb file it’s a Debian installer, you can use dpkg to install it.
sudo dpkg -i /home/your user name here/Downloads/trezor-bridge_2.027_amd64.deb
Insert your password and press enter.
You can also, right click on it, select “open with another app” and choose “software installation?..” my system is in another language but should be something like that, and you will be able to install it from there.