You can think of it like water. Volts are the speed of the water, AMPs are volume of water passing through. So when headlights or starter goes - it takes a lot of 'water' to make them go.
And that's why it takes a big hose (heavy gauge wire) to things that use a lot of 'water' or 'current'. Eh eh eh? Get it? Big pipe, lots o water, lots o amps, lots o current?
