A lot of people I speak to are really intimidated by electrical systems.  Here is a series of videos that might give you the fundamentals.  The full playlist on YouTube is here.  If you’re looking for a good reference book on motorcycle electrics, this is a good one, and there are more book recommendations on this page.

Electrical 101 – Voltage

Electrical 102 – Series circuits

Electrical 103 – Parallel circuits

Electrical 104 – Resistance

Electrical 105 – Wires (conductors)

Electrical 106 – Soldering

Electrical 107 – Crimp connectors