OSMC kernel has drivers for a lot of wifi adapters.
Go in terminal and type ‘dmesg’ to see if your wifi adapter is recognized (if you don’t konw how to find it, unplug and plug the adapter and you shold see something on the latest lines of dmesg output).
Then, follow these steps:
$ sudo cat /var/lib/connman/settings
You should see somthing like this:
[WiFi]
Enable=true
Tethering=false
If WiFi is setted to false:
$ sudo nano /var/lib/connman/settings
Change ‘false’ to ‘true’, hit ‘control key’, type ‘Y’ to save.
$ sudo reboot
Open terminal again, then:
$ connmanctl
connmanctl> agent on
connmanctl> scan wireless
connmanctl> services
(you should see your wifi network called “wifi_somethingsomething_managed_psk”)
connmanctl> connect wifi_somethingsomething_managed_psk
(the agent will ask for passphrase)
connmanctl> quit