Understanding how PCB CAD designs affect the final product
To make a pcb you need to have the information required for every layer the board house needs (copper, soldermask, silk and the board outline). These layers are typically sent via so called gerber files. 

The PCB Layout software uses footprints that define the interface with every component (Pads in a footprint define the places where the leads are soldered to, graphics on technical layers help for documentation like silk screen)

To define which pads need to be connected with traces (or other means) you use the connectivity information that you get from the schematic.

The schematic is build up from symbols that are the abstract view of the function of every component (The schematic is then the abstract view of the systems intended function)
Symbols define pins that are mapped to footprint pads (via the pin/pad numbers and the footprint field of the symbol). You define the connectivity information by using wires that are used to connect pins together. (or you can also use labels or power symbols)



I have made a KiCad version 5.1 specific tutorial that shows the minimum requirement for getting a finished board designed. https://forum.kicad.info/t/tutorial-introduction-to-pcb-design-with-kicad-version-5-1-getting-started/20600/

There are other similar tutorials out there. Some also as videos if you prefer that style. But make sure they really use the correct version of KiCad as the interface is quite different between different major versions.