Before looking at how this works, let's look at what it does.
Here is a prototype of a user interface,
the IO markers at the bottom represent the pins in your breadboard,
and the horizontal lines represent channels, or jumpers to which the IO pins can be connected.
Finally, we also have addons, which are useful tools or features which can act on channels,
in this case we see an ADC addon reading the signal on channels 0, 3 and 4.
Here we can see the IO 0 pin connected to channel 6, and the second not connected. If we were to connect IO 1 to channel 6, we would have a connection between the two pins which we can monitor with the ADC addon.