Check that a LAN cable is connected to the LAN port of this machine via the network.
Ensure that this machine has an IP address assigned to it. Tap [Utility] - [Device Information], and check that an IP address is displayed.
If no IP address is displayed, you need to set up the network. For details, refer to Here.
Check that the appropriate settings are configured to use this machine as a scanner. (You can use this function with the default settings unless otherwise requested.)
How to configure the setting is explained using Web Connection. For details, refer to Here.