Electronic – How to add ground to DC circuit

dcgroundgrounding

I'm just a dabbler in electronic circuits and I'm really still kind of a noob. I am working on a project called the "Atari Punk Console" (Originally known as the "Stepped Tone Generator") but there are some parts of the wiring schematic that I don't understand, specifically the parts with the ground symbol.

Here is the schematic:
enter image description here

See those two ground symbols? I don't understand how to properly connect the circuit to ground at these points. How can I do this and be sure that I did it properly. I don't understand grounding at all so any pointers or clarification is also welcome. Thanks in advance.

Best Answer

What isn't shown on your schematic is that the negative terminal of the 9 volt supply is connected to all of the other ground symbols, which are all connected together.