You basically just install steam from within your linux distributions package manager. I use and recommend some arch based distro but for Ubuntu it should be ap

You basically just install steam from within your linux distributions package manager. I use and recommend some arch based distro but for Ubuntu it should be apt-get or some gui tool like synaptic. After you installed steam it will probably just work. You might need to go into settings -> steam play and enable proton. that's it.