US Elections -- How do they work?

The US election season that started in early 2015 has now gained momentum with the elections for the Republican and Democratic parties underway. And the interest even in other countries such as India is picking up.
Surprisingly, most people had a similar question. How exactly do the US elections work ? And even more surprisingly very few had any idea. My attempts to explain were to put it mildly, hugely unsuccessful.

And so I did, what I do when I'm stuck. Find someone who could do it better. I first explored websites and wikis and pdf's and ... They were extensive but drab and boring. And I didn't think too many people would take the trouble to read so much matter. I thought maybe videos could do a better job. And there were several. After gong through over 2 dozen videos, I managed to narrow down to 2 which between them would give a good idea of the US Government and election systems, including of course the Presidential elections.

The irony is that both of these videos are by UK organizations. The UK Parliament and The Telegraph.


UK Parliament
This is the official YouTube channel for the UK Parliament

The Telegraph
The Telegraph is the most popular UK newspaper on YouTube.