title: How to append a "non-free" component to /etc/apt/sources.list. Steam install
body: <p>I have bought a chromebook and it has come with the os Debian Linux system of which I have no idea how to use or work. I am trying to install Steam on my computer and am following this tutorial: <a href="https://wiki.debian.org/Steam#A64-bit_systems_.28amd64.29" rel="nofollow noreferrer">https://wiki.debian.org/Steam#A64-bit_systems_.28amd64.29</a></p>
  <p>I have fallen upon the first step as I am trying to create a new list or even append this non-free component to the current <code>sources.list</code>. However I am confused as to how to append it as running the command <code>deb http://deb.debian.org/debian/ buster main contrib non-free</code> I am told <code>deb</code> is not a command. This would be fine if I then knew how to create a list and add it.</p>
  <p>Would someone be able to help me as to how to add this non-free component to the source.list file. My understanding is very basic.</p>
  <p>Thanks</p>