Step 0: SSH into the server
You will be provided with a domain name looking like
xxxxx.ubucon.abolivier.bzh, which points to your dedicated VPS.
To access the server's command line, run
ssh firstname.lastname@example.org from a terminal (or connect with your favourite SSH client with the user
ubuntu), and use the password
Step 1: Install the Matrix.org repository
wget -qO - https://packages.matrix.org/debian/matrix-org-archive-keyring.gpg | sudo apt-key add - sudo add-apt-repository "deb https://packages.matrix.org/debian/ bionic main"