If this is your first GUI install then you need the Standard GUI Full version from the CD included with your analyzer or available from the Avcom website’s Download page. Once you have installed the GUI look for the Spectrum Analyzer List control box and you will see several items called Slot#1 through Slot#4. These are various model analyzers located in Richmond, Virginia, USA. Select one of these Spectrum Analyzer List items for the GUI to connect to them and you can control and tune those analyzers remotely. If you cannot connect to one it is because someone else is using that analyzer. For multiple users to connect to the same analyzer all GUIs must have their GUI Network feature enabled and this is not practical to configure for unrelated customers. There is a PDF manual in the GUI menu under Help – Open GUI User Guide.