To use the Signal desktop app, Signal must first be installed on your phone.
Linux (Debian-based) Install Instructions
# NOTE: These instructions only work for 64-bit Debian-based
# Linux distributions such as Ubuntu, Mint etc.
# 1. Install our official public software signing key:
wget -O- /desktop/apt/keys.asc | gpg --dearmor > signal-desktop-keyring.gpg
cat signal-desktop-keyring.gpg | sudo tee /usr/share/keyrings/signal-desktop-keyring.gpg > /dev/null
# 2. Add our repository to your list of repositories:
echo 'deb [arch=amd64 signed-by=/usr/share/keyrings/signal-desktop-keyring.gpg] /desktop/apt xenial main' |\
sudo tee /etc/apt/sources.list.d/signal-xenial.list
# 3. Update your package database and install Signal:
sudo apt update && sudo apt install signal-desktop