Electrical expertise…

Any good sources of knowledge in regards to building an electrical circuit….

As part of the E Kart I’m building need to obviously get the motor and various wiring etc

Whilst I can buy a complete kit, electrics is one area I’m weak in so would like to build it from scratch but need to learn more about the subject

For example looking at motor, working out the power supply it will need, wiring up the motor to accelerator pedal, power controller, would also want to add a reverse gear

Any good books/sources of information