linuxmemes

Honestly, depends what helps you learn the best. I would recommend at first use Linux Mint, it's ubuntu without the bullshit, will look familiar to you and use that as a way to learn more. Or Pop_OS if you want something a little bit more different from the windows interface. I would also recommend YT channels like The Linux Experiment, DistroTube and Chris Tech Tips. I will also recommend the Arch wiki (even though Linux Mint is not based on Arch it can still be helpful), install tldr for short descriptions of terminal commands, use man for long descriptions, and so on.

In general the best way is fuck around and find out (keep regular backups). Don't be scared of messing around or fixing stuff, it can be easy and of it isn't an OS reinstall will take about 15 minutes anyways so you're good.

Also depends on what you wanna do. If you justbwant to browse the web and use a few common programs you can just install Linux Mint and remember to install programs via the package manager (app store) and you're generally good. Gaming? Use Steam (enable the proton compatibility mode) whenever possible, lutris should be able to handle the rest. And lastly also look at AlternativeTo when you find programs that aren't available or you don't like.