Linux

You want a quick how-to?

1.) Ordinarily I'd say the first step is to make a list of every app you regularly use and make sure it works in Linux (or that there's a viable alternative for Linux), but outside of CAD, Photoshop, and a few holdout games, this isn't really an issue anymore.

2.) Backup everything that matters to you.

3.) Pick a desktop environment before you pick a distro. The distro almost doesn't even matter. The most popular options are GNOME and KDE. I assume XFCE (my favorite) and Cinnamon are a distant third and fourth.

4.) Pick a beginner distro (like Mint, PopOS, Garuda, Fedora, or whatever else gets recommended in the comments) that has an edition for your preferred DE. (Just check the download section of their websites.)

5.) Grab an old thumb drive. 4GB is plenty, last I checked.

6.) Go to the website of your preferred distro. Download an ISO file.

7.) Download a program to flash the ISO onto your thumb drive. Balena Etcher is one. Run it, and flash the ISO.

8.) Shutdown your computer. On restart, spam the escape key, or maybe some of the F keys, depending on your computer. Instead of booting normally, you should get a menu.

9.) Navigate through the menus and disable secure boot and TPM. Then under boot order, move the USB to the top of the list.

10.) Restart, hopefully loading the USB's live environment.

11.) Play around in the live environment before installing. Test something with sound. Maybe load a youtube video or something. Make sure everything works.

12.) Run through the installer. Reboot. Spam esc/F10/whatever and get back into the BIOS menu. Reset boot priority to boot from hard drive. Reboot.

13.) Run through the steps on whatever welcome screen you see. If not prompted, update your system first thing. You can figure out the rest from there.