My A Level subjects don't reflect my desired degree in my personal statement

Hey guys, I currently do media studies, business and graphics but have had a huge change of heart and wanted to pursue a career in computer science/IT.

Although I've found many superb courses that don't require any relevant A Level subjects, I don't know how I could reflect myself properly in my personal statement in line to doing computer science because none of my A Levels are relevant to computer science.

So what do I do? How can I write a relevant personal statement that shows I am dedicated and able to get into the degree?

Don’t bother mentioning your subjects.

Just make sure you have plenty of relevant supercurriculars, do your wider reading and can show you have a strong interest in computer science.

Wow! Never knew you could just not mention your subjects at all! What sort of super curriculars can I do, sorry if I sound dumb.

Yeah, I only learned recently that you aren’t actually meant to mention your subjects in your PS and how they benefit you as that is quite impersonal and wastes space.

I for one have no experience with computer science whatsoever, so I am perhaps not the best person to ask.
What I have done, however, is a quick google search and I found this: https://www.undergraduate.study.cam.ac.uk/files/publications/super-curricular_suggestions.pdf#page9

That may be worth a look.