I want to connect a function generator to this circuit, but I does not work
how can I connect the signal generator with my circuit?

 

How can you expect anyone to answer such a fuzzy question in relation to such a fuzzy schematic?

Are we supposed to somehow just know why you want to connect a function generator to this circuit in the first place?

Are we supposed to somehow just know what they heck this circuit does, given that it is mostly two boxes labeled "Subsystem" and "Subsystem1"?

Most of us here have returned our crystal balls to the manufacturer because they just seemed to be defective.