Some of the System resources functions are a little thin on examples in the User Manual and in the Reference Manual.
One way I've learned about them is just to drag one from the System resources folders on the right onto the screen. This creates a Data Box object with the resource as the data source.
You'll see, for example, that the Data Box has a "General" type with the argument "GetInterfaceStatus(0)" in it.
I just used that the other day; "GetInterfaceStatus(1)" returned the string "Up" or "Down" that reflected the actual Ethernet (interface 1) Link status.
The context-sensitive Help in Crimson usually leads to the Reference manual; if you highlight the System Resource and press F1, you are usually taken right to the appropriate page of the Reference Manual PDF.