Without sitting in front of your machine it is hard to diagnose, so apologies if these questions seem pedantic.
This is was what I did from memory:
- I downloaded the zip file to a PC
- I inserted the sd card into the pc and from memory a window utility popped up to take me through the copy process. i believe this offered a facility to format the sd card which i did
- i copied the zip file to the sd card
then i followed the instructions in the web link after putting the sd card in the t8.
a quick check you can do to ensure the copy process has worked
- with the t8 switched on and the sd card not mounted.
- mount the sd card
- use es explorer to view the sd card
- do you see the zip file and nothing else?
try all that and report back.
fyi although the t8 supported auto updating of android apps and kodi and its addons, it was the firmware update you are trying to apply which provided ota functionality to older t8's.
even with that, ota updates on all machines do not "auto update". they allow you to download firmware updates to your android box and then you manually apply them.