I read ‘All you need to know about the City’ by Stoakes which I’d definitely recommend but sadly it’s not all you need to know: some parts are too basic, some too detailed and some irrelevant (I’m thinking the stuff on the reinsurance market).
I’d recommend a combination of The Economist (magazine and podcasts), BBC News (basic) and the FT (detailed). For finance terms Investopedia is good.
One of the most useful things I did was to summarise The Economist/recurring FT stories weekly and every time I didn’t understand something I’d research it until I did. Developing commercial awareness is like learning a new language: the best way to learn is to immerse yourself. I started out really unfocused but I slowly picked up how things connect with each other because I kept trying.