I don't know if there has been a post on this or not, but I could not find one.
If you're having troubles using SpringClient to set up a LAN games, here is what to do:
1)Make sure to choose a port that is open on your firewall when you create a server.
2)Goto file->configuration and change your IP address to your local IP address (i.e. 192.168.0.17 or whatever it is on your local network) instead of your public ip address (i.e. 207.141.141.99).
3)You and other people on your local network should be able to set up, join, and start a game on Spring. Nonlocal players will not be able to join.