In this video, we introduce the concept of "transactions" which are the means by which value is transferred between parties in bitcoin.
Bitcoin is commonly referred to as digital cash, and here we look at some simple real world cash transactions and show that they can be represented as a chain of transaction records where the output of one transaction (the payee receiving the cash) enables that payee to in turn become the payer of a subsequent transaction by handing over that same cash.
So we start by thinking of these transaction "documents" as simply records of real world transactions, but then I introduce the idea that such documents could potentially replace coins altogether and be the mechanism of value transfer themselves.
Once you understand this, you are well on the way to understanding the real fundamental concepts behind bitcoin.
I also show how the Blockchain in bitcoin is really on the mechanism by which these transactions are stored in a safe way, that is tamper proof and does not rely on any one party for trustworthiness or availability.
Any questions, please ask below - I know some of the content here is quite abstract so any questions you ask will probably help other people as well.