Install-WindowsFeature : The term 'Install-WindowsFeature' is not recognised...
You want to import the ServerManager module, only to be greeted by another error:
Import-Module : The specified module 'ServerManager' was not loaded because no valid module file was found in any module directory.
You do all sorts of black magic to make ServerManager load, perhaps you copy C:\Windows\System32\WindowsPowerShell\v1.0\Modules\ServerManager to C:\Users\<your_account>\Documents\WindowsPowerShell\Modules\ServerManager. You'll eventually get to load ServerManager, and you breathe easy - until you try to install the prerequisites. Then comes the shock:
Install-WindowsFeature : The target of the specified cmdlet cannot be a Windows client-based operating system.
WHAAAT? Heck, your're machine is Server 2016!
Well, my friend, did you notice the "(x86)" bit in your PowerShell window's caption?
Yes, you're running a 32-bit PowerShell on a 64-bit server.
I can't blame you, it's easy to just type PowerShell and hit Enter. The problem is that the default selection may bring up the link for the wrong architecture:
The fix? Launch the 64-bit version of PowerShell and you'll be laughing.
Enjoy.