There are a variety of ways to tell LAN Speed Test where you want to test and this is the place to do that.
If testing with LST Server, then you enter the location (ip address or computer name) of the computer running LST Server. When LST Server 4.0 is released, LAN Speed Test will be able to find LST Server automatically by clicking on the '...' button.
Here are some examples...
-> 192.168.0.1 (LST Server is on computer at this IP address)
-> 192.168.0.1:1234 (LST Server is on computer at this IP address listening on port 1234)
-> server.totusoft.com (LST Server is on computer with this DNS Name)
-> http://server.totusoft.com (Same as above)
-> server (LST Server is on computer with this name)
Remember, the server's ip address is displayed on LST Server's main screen.