I have a slight interest in this topic as i've had intermittent AF since my early 20's and will no doubt be offered statins at some point earlier than most.
This YouTube doctor is a working, British cardiologist who makes often entertaining videos on a range of health topics, but importantly is always evidence based with no quackery (actually he does quite a lot of quackery exposing). I subscribe, there's a lot of interesting stuff he's put out. This is a pretty straight up explanation of statins, without his usual added humour: