How to upgrade from OS X El Capitan 10.11.6 to macOS Sierra 10.12.6
You have downloaded some updater files for macOS Sierra which require at least an already installed macOS Sierra 10.12.

They are useless if OS X 10.11 El Capitan is installed.

Go to the App Store, download the macOS Sierra installer and install it. If it isn't available the following trick may help:


  Mission accomplished: after installing this command-line tool ('https://github.com/mas-cli/mas'), the command
  mas install 1127487414
  purchased*, downloaded, and installed version 10.12.6 of correctly.
  
  * By which I mean, the program not only downloaded Sierra, it did so using the Apple-supplied App Store frameworks in /System/Library/PrivateFrameworks, resulting in an application bundle containing a properly-signed MAS receipt linked to my Apple ID.


or try bmike's answer.