Before using Network Clipboard for the first time, you need to configure some quick settings.
The most important is the list of Computers and Users allowed to access your Network Clipboard (you may consider just configure Computers... Users may be added if Learning Mode is enabled), but is not recommended the use of learning mode (to avoid interruptions in your work).
You may add user names with wildcards.
You may add Computers names on your network manually, or just click the Scan button on Network Settings (Main Menu :: Options :: Preferences :: Network Settings).
You are allowed to enter computer's names with wildcards.
Make sure all Network Clipboards on your lan uses the same default port and if you use a firewall please don't forget to create a rule to allow Network Clipboard to work as Server and to use specified default port.
See Also: How to configure TCP/IP Protocol, Windows Firewall.