This website explains the concept of bitcoins and the blockchain in a very interactive manner:
https://www.socratease.in/chapters/intro-to-bitcoins-1.Even if you start with zero knowledge about bitcoins, you should be able to understand the overall architecture within a couple of modules.
Full Disclosure: I am the creator of the platform and the content. I am posting here to get feedback from non-experts to see if they found the resource useful, and from experts to see if they would want things changed.
