supercuriculars

Basically, it gives you a range of things to talk about in your personal statement, and gives a good background to the A-Level knowledge you've gained. It shows an active interest in a subject area, rather than just passivity in taking in info.

As to how to do it, well, it all depends. I simply read a bunch of wikipedia pages when Numberphile would do an interesting concept, and I attended a talk in Oxford when I was there for the open days. I also ended up doing some maths challenges and that Project Euler thing.

Ruby Granger does some good things on supercurriculars dotted through her videos. She does things like reading books and making annotations on bits she does and doesn't like, she writes essays on themes in books, she listens to podcasts, and talks on services like the Great Courses Plus.

Reading around your subject means reading books, articles or watching YT videos to expand your knowledge, particularly in the topics you are currently studying. For example, sometime ago in Psychology I learnt that stimulus association in dogs creates a conditioned response and makes them salivate when a bell is rung. So I then wondered how this related to humans. And then I began digging deeper into human psychology and learnt about dopamine. Then I learnt how everyday people have become conditioned to seek dopamine through constant entertainment (social media, movies, Netflix etc.)

You see what I mean? Because something sparked my curiosity I decided to dig deeper and learn a whole lot more. That allows you to gain a greater understanding and enhance your learning.