Assuming Alex uses Windows 10 or 11 as a daily driver, then WSL 2 is an obvious first step. You can pick a distro from the Windows Store (newbies might be advised to go for Ubuntu simply for popularity reasons) and there's even support now to run graphical Linux programs while staying in the Windows desktop.
If you're after the full Linux graphical desktop experience, then maybe Virtualbox running a Linux VM would be your next step. If you really want to get your hands dirty, dual booting Linux and Windows on bare metal can be an option (I'm assuming Alex wouldn't be in a place to give up Windows entirely at this point).
Be warned that you should put Linux on a separate physical drive from Windows in a dual boot setup. If they share the same drive, Windows will wipe the Linux bootloader (usually Grub) when Windows updates (which is outrageous, but that's Microsoft for you), meaning the machine will revert to exclusively booting to Windows only again. This is fixable, but involves booting into a live Linux distro and re-installing Grub, which is beyond most newbies' skill level.
If you're looking to take the final leap and remove Windows completely, then you're going to have to make sure Linux can run all the app/games you consider "essential". There's bound to be some of those that are Windows-only and don't run acceptably or at all on Linux, even using translation layers like WINE/Proton. You might be able to find close cross-platform alternatives (think Firefox, Thunderbird, LibreOffice, GIMP, VLC, Audacity, OBS etc.) that you can run on both Windows and Linux for a while to get used to them before dumping Windows.
As for me, I was dual booting for many years, with Linux being my primary desktop and Windows booted into exclusively to play games. With Steam's Proton, Lutris, Heroic Games Launcher and the fact I don't play multi-player games, almost every single game I have works in Linux now. When I got a new PC in Dec 2022, I only installed Linux on it and also wiped Windows off my old PC, so I finished the journey a year ago that Alex is just starting. It's great my entire house is now Windows-free and, yes, I've got a Steam Deck with SteamOS on it of course. Windows, to me, was only good for gaming and Linux has mostly caught up in that area, which used to be its only weakness.