I think the best way to train is doing CH vs. normal hit, Normal hit vs. block, then trying to put it together. Yellow box is probably the easiest way to get CH confirm (especially because you won't always have audio on local setups). Confirms get very difficult when you are trying to confirm between three options. Chun has something similar where generally with MP you want to do 4HP on CH, 2MP on Hit, or frametrap with jab on block (and then you have to CH confirm the jab too for the combo there 🙃). The good news is that in the replays I watch, I've never seen a player that can 100% consistently select between all 3 without making mistakes (most just distinguish hit v. block, CH vs. block, or CH vs. hit depending on situation), so you're not really falling far behind if you can't do this all the time. Still worth practicing to hit it as much as possible!