total beginner here, why are the colour wheels doing absolutely nothing to my video?

https://preview.redd.it/2hlmfuo8x93h1.png?width=1919&format=png&auto=webp&s=a05feac80ac45969f7f5bd6eb1c3bc29af84081a

I've just started using Davinci and it looks really promising, but I can't get these colour wheels to work, or any of the built-in colour features. I have no idea what i'm doing wrong, as no tutorial I watch explains anything like this, they just head straight into messing with the colours from what I've seen.

Does anyone have an answer?

Thank you so much for reading this.