How do I undo command-control-3 desktop reorganization and restore background on Mac?

Hi,

I have 2 questions:

1. I was supposed to take a screenshot, but I pressed command-control-3 and it reorganised my desktop to put my things into folders like "2024", "2025", "previous" and "last 30 days". This is really annoying, and I'd like for it just to go back to normal. I have tried command Z but it can only undo things i have done after I made the mistake. Does anyone know how I undo this?
2. My background is just a bright yellow screen every time I turn my computer on and it has removed my chosen backgrounds. Anyone know how to stop this?

Thank you so much!

Kindes regards,

Camilla

[Re-Titled by Moderator]

Original Title: command-control-3 help :)