To use your laptop on a WiFi network, you need some WiFi entrypoint/router with DHCP service enabled. This router provides your laptop with a valid IP address during startup. You won't get it from your desktop. You also need that router to 'route' / direct your network trafic, without it it gets lost.
I don't know what network components you have and what is available in your country. May be it's worthwile to visit a local computer store and ask for advice.