I've now had an answer from elsewhere on where I've gone wrong with this and where I need to direct my attention to get a better picture, so please continue to ignore this post!
Hi, I'm unsure if I'm posting this in the correct place, so apologies in advance if not. I looked at the study board, but the post template doesn't apply to my question.
I'm a layperson who had previously only read popular science books on QM, but has recently been watching some more...