Basic set up guide here.
You can also check other parts of the knowledge base for more info on the T8/T8S/T8S+ series boxes.
These boxes are quite old now and a lot of the software mentioned in the knowledge base is out of date or no longer available. But you should be able to find some working alternatives (my old t8S plus used to run a lot of newer stuff). It matters that you box is running android 5 or later as later apps may not run on 4.4.2.
This video shows a typical first boot with our DroiX® T8-S Plus model.
droix.co.uk