1. First, I'd master database and cryptography fundamentals, with something like Dan Boneh's course for the latter
2. Then, I'd read the Bitcoin.org and Ethereum documentation
3. Then, you should write short Python or Go scripts to do things like printing out the blockchain, formatting and signing a transaction by hand, managing private keys, that type of thing. This will give you a feel for the raw data structures.
4. After doing all this, I'd take a look at application libraries like Ryan Shea and Muneeb Ali's new blockstack.org
The reason I'd do it in this order is that you would learn fundamentals first before proceeding to the cutting edge.