I have a fibre connection to the internet, and two Deco X20 devices.  Everything is working well - devices using wifi connect to the internet.  Two PCs are connected to the modem by ethernet cable - they are on the LAN.  Machines on the wifi network cannot see machines on the LAN, and vice versa.  Network discovery is turned on on all these machines.  I want to be able to transfer files between laptop and PC, and also I want the laptops to use the network printer.  How can I connect the wifi network to the LAN?