I'm probably not the right person to ask about this because I've used linux for, in real time, maybe about 50 hours. I'm only used to using the command line for stuff because I did a lot of this on mac, and mac's terminal is basically the same thing. Though I recognise that "use macos for several years before trying linux" is not actually the most helpful advice.

The other thing is that the specific linux thing I'm using to get the fishtank cube is a bit janky and not the most user-friendly, and there might be other options that are easier, but Compiz (which provides the effect) is kind of old and not really used as much anymore. Like, I couldn't install Steam by downloading it off the website because it would only download a Debian version, so I went to install it off flathub (allegedly the "linux app store"), but for some reason this version of fedora doesn't come with flatpak (program that does the installation of stuff from flathub) so I had to install that, and there were four apparently identical versions of flatpak to choose from, and I chose wrong and got a cursed version of flatpak that seemed to work but actually thought flathub had no apps in it, which I thought was a problem with flathub. The solution was to install flatpak from the command line instead of the gui, which made it automatically pick the right version. And then I could install Steam. (Also if you want to play windows games on linux on steam you gottta go into the properties for each game and turn on "force the use of a specific compatibility tool", but that's the same for every linux).

Although I'm googling this now and there is apparently a version of ubuntu that uses MATE, and that lets you install and use compiz. Everybody recommends ubuntu for first time linux users because it's meant to be easy, so that is probably a better idea. I don't know for sure, I've never tried it.

Anyway, migrating files is just a matter of putting them on an external drive or someplace else you can access them and copying the files over from within linux. Applications are harder; linux can run (most) windows applications with a program called "Wine", which often surprises me by how good it is; any portable applications you have (i.e .exe file sitting in folder instead of stuff you had to run an installer for) can probably just be copied over and run as normal. Everything else you've got to reinstall, either with Wine or preferably by downloading a native linux version (which isn't always available). Ubuntu-mate apparently has a "software boutique" which has the ability to install an app store-ish program just called "Software". No idea why they set it up like that. But hopefully it should more or less work. In any case expect the process of installing all the applications you want and getting them set up properly to take like, a day. And some programs (notably adobe creative cloud and microsoft office programs) just will not work on linux, unfortunately. There will almost always be an alternative (like "libreoffice"), but it might not be quite as good as you're used to.

On the subject of the command line, if you can paste commands into powershell you can paste them into bash!* But it helps to get a feel for how the command line works and how to use it. There are a million tutorials for this, here's my favourite. If you want to practice on windows you can install the "windows subsystem for linux", which gives you access to a genuine linux terminal within windows you can play with. You probably won't have to use the command line all that often, but it is useful. Imagemagick is a great program for basic image editing and it's command-line only, for example.

Also a couple things about installing linux. The general process is, you download an iso file for the linux you're installing, you use "Balena Etcher" or something to put it on a usb stick, you turn off your computer, you turn it back on while holding the button that lets you select what drive to boot from (this varies by what model of computer you have, you can probably google it), you select the usb stick, and then you have a "live session" of the thing you're installing. You haven't installed it yet but you get to test it out almost as if you have, which I highly recommend. Oh wait they actually have a guide for installing and everything else, that's nice. The second thing is that you can partition your hard drive so it has both windows and linux on it, and then you can just hold the button down again to pick which one you want when you turn your computer on. (hint: if the linux installer sucks and won't shrink the windows volume for you, use "aomei partition assistant" from windows, i know it looks like a scam and i think it is somehow but it does at least work). I extremely recommend this, because it means if for whatever reason you need to abandon linux you have an easy way out, and if there's anything that you need windows for you can still use it. And doing it this way means you won't necessarily wipe all your files when installing it. You still might though, so you really should make a backup to an external drive first just in case.

Ok that's everything I can think of. I wish you the best of luck!

*errata: to be clear I mean that pasting things is the same skill for both, not that powershell commands work in bash