When installing MacOS Sierra, you will be prompted to activate Siri on your computer.
Once enabled Siri should work without any further intervention, however there are a few adjustments you can make.
Navigate to System Preferences, then click the Siri icon.
An appropriate language should automatically be chosen depending on your system settings.
You can decide if Siri is male or female, or switch off voice feedback completely if you’d prefer not to be spoken to at all.
You can then choose an alternate microphone.
There are a small selection of keyboard shorts cuts to activate Siri, plus you can add a key command of your own.
An icon will appear at the top right of your screen if you enable Show Siri in menu bar.
In our experience the icon didn’t appear despite the box being checked. Deselecting then selecting the option again prompted the icon to appear.