I interpreted the question as "learning how bitcoin works" so I'll say that as a programmer, this guide:

Is the most in depth and explanatory guide of a system I've seen in many years. It goes from the most basic of basics (what is an addresss?), through transactions, multisigs, and all the way to and including Lightning, and as you are doing what you're reading (sending TXs, writing Script) you get a lot out of it.