Signal networks should be conceived of as dynamic patterns that change over time.
A psychological example of this might be a short exchange between two people during which one person interprets a small signal coming from the other.
The signal might be a fleeting expression. The person who sees this signal is likely to interpret it and remember (weakly or strongly, for some period of time) what that interpretation is.
As something held in memory—short or long term—that interpretation of the fleeting expression has become both itself a signal and part of a signal network that is changing over time, changing in part due to that new signal.
Of great importance psychologically for both persons described above is the fact that neither knows how the other interpreted the fleeting expression or if it was interpreted or sent or received. Or remembered or for how long. And almost never do they know how to get that information.
This is a micro example of human communication as it happens in time.
If this micro signaling network is held in the mind and analyzed correctly by the two persons described above, much will be revealed to both of them about how their psychologies actually function in real life and real-time.
FIML practice is designed to get them to that point.