I'm trying to upgrade from El Capitan 10.11.6 to the latest version of Sierra 10.12.x.
I'm following this tutorial which recommends getting Sierra through the App Store.
However when I open the App Store and go to the Updates tab, I do not see Sierra as an option, only upgrading security patches for my existing 10.11.6 installation:
What's going on here? How can I find 10.12.x and upgrade to it?