Im new here, and i found this Tablet, dont know what to do

[S5 M5]

Hello, I have found a tablet attached to a usb keyboard trown outside. i picked it up and charged it, just for me to see a strange screen that i cant get pass trough. how can i flash in an android firmware? i opened it up and it has a A31s Quadcore processor from Allwinnertech.  Any help is appreciated thanks