MetaMask's Dan Finlay gives a basic technical overview of how Ethereum and blockchains work at the opening talks of the IPFS Ethererum Hackathon, Seattle 2017. He explains the Merkle Tree very well with a neat color tree that illustrates how things change when things in the chain change. Visualizing this should help you understand the foundation of blockchains and other technology built using Merkle Trees. Wiki has a great written explanation of Merkle Trees https://en.wikipedia.org/wiki/Merkle_tree but this video is one of the best I have seen explaining things that you need to know to start building on Ethereum or Steem or EOS.
