Neurophone circuit, what's wrong here?

Question

Electronics

It is not clear:
1 - There are 8 GNDs on this circuit, do I need to close them together?
2 - Input goes to the capacitor and where to hook the other end? to GND?

Answer 1

1 - yes
2 input - this is the input from your sensor. Attach it to a container. And further according to the scheme.