Jacks come in two flavors and the rule is simple. Learn the one-output, many-inputs convention that governs every patch you will ever build.
Jacks come in two flavors: inputs and outputs. The rule is simple.
An output is a signal coming out of a module. A VCO output is the sound it makes. An input is a place where a signal goes in. A VCA input is the audio it will process.
One output can go to many inputs. Many outputs cannot share one input - the last cable wins. Most panels put outputs near the bottom and inputs near the top, but labels always tell you which is which.
Tip
Look at the rack on the right. Trace the cables. VCO output to VCA input, VCA output to Output input. Signal always flows left to right, top to bottom, through the patch.