Buka Software Sources. Pilih "Additional repositories", lalu klik "Add". Tempel (paste) . Buka Terminal, lalu ketiklah . Ketiklah . Buka Software Center, lalu ikuti instruksi yang diberikan di dalam proses pemasangan Steam untuk Ubuntu.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Steam is not included in the Mint repository, so you'll need to add it manually first before installing it. You can install Steam from the Steam website without doing this, but then you'll have to manually update it each time an update is released (which is very often).  deb http://repo.steampowered.com/steam/ precise steam into the address bar. sudo apt-get update. This will update your repositories. wget -O - http://repo.steampowered.com/steam/signature.gpg . Press ↵ Enter to run the command.