Looking for help

Hi!
I love baking. I’m a 20 year old student and live in Wales, UK.
I’m wondering if someone could help me…
I want to start posting pictures of my cakes on social media and if someone was to be interested in buying a cake, I’d love to make one for them!
Could someone fill me in on all the legal requirements and registration I would need to sell cakes on such a small basis?

Thank you so much!!
Jess xx