In the program addons you will see one called CoreELEC Module Drivers and when you run it you will be presented with the option to choose the DVB driver module.
Then, when you select that, there will be 3 further options.
Choose the first one ‘Corelec default drivers’ and then reboot for it to be enabled and see if the tuner is seen.
If not, go through the same process again with each of the remaining two options.
At least if things don’t work after that then you will have tried the basic necessary steps to start with.
Are you using TVHeadend to verify the recognition?