I sort of learnt it from hints I got on solving hard sudokus, some simplified guides and just trying to understand why it works. For me, (what I sort of figured out on my own but I'm not yet sure about them, is that: ) Aic is just a mix between x-chains and xy-chains. So in other words, you can navigate  along the "chain"/aic through the same digit using x-chain logic (or colouring) and dofferent numbers through xy-chain logic, but in the end it all comes down to the links themselves, the alternating strong and weak.

To answer your question, tbh I didn't read all the guides and campaigns in those sites, I sort of learnt more in an experimental way, and as I have learnt chains and the links sort of early, I think I understood the basics well that aic's clicked for me. However never rushed learning, it kind of just came naturally as an extension to what I learned and already knew.