GX450 route LAN to Wifi

We’ve a GX450 client that will be connected to a WiFi network. We would like to allow clients from LAN interface to connect to Internet through the Wifi connection of GX450 but we’re not able to configure correctly the device.
The device is connected to Wifi as an AP but clients from LAN are not able to connect to internet.
How can GX450 have to be configured to work in this way ?