Steam can be install as a flatpak package in all currently supported versions of Ubuntu. Open the terminal and type:
sudo add-apt-repository ppa:alexlarsson/flatpak # required in 16.04 only, not in later releases
sudo apt update
sudo apt install flatpak
sudo flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak install flathub com.valvesoftware.Steam
Steam can be launched by clicking on its icon in the Dash or launched from the terminal with the following command:
flatpak run com.valvesoftware.Steam
Many games require an online purchase, but some popular games, such as Team Fortress 2, are free to play. When searching in the store, be sure to narrow results by the SteamOS/Linux operating system. Not all Linux games are compatible with your system, so make sure you check the requirements before purchasing games.
http://store.steampowered.com/about/
. If you meet any error dosudo apt-get -f install
to install dependencies.