Beginner in need of real help!

If you try to spin up multiple services but get stuck on creating a directory, you're moving too fast. I think you'll need to start a bit slower and more structured.

Learn how to do basic tasks in the terminal and a bit about how linux works in general. There is a learning curve, but it will be fun! Then move on to docker and get one service up and running. Go on from there with everything you learned along the way and solve the other problems you'll encounter - one at a time.

Change "user" to your actual user name.

Yeah, as someone else mentioned, this step is just for creating a folder. You probably need to get more intimate with the commands you're running to understand the process better, but I would honestly take a step back and use something more streamlined for these things.

Someone mentioned Proxmox for these things. I would also mention TrueNAS Scale. Both of those make it so that the process of spinning up containers and VMs becomes a lot more streamlined and easy to follow. They also forego a UI on the equipment you're using, opting for a web UI you'd access from another device instead. Make no mistake, this is a good thing. 99% of things you'll be wanting to do anywhere will be through web UIs, so that's where you'll want to be. The 1% of the time where you'll be seeing your laptop server's screen (or an SSH terminal) will be the most painful 1% of your life, and it will be when you misconfigured something and the web UI becomes inaccessible (on that note, also make sure to at least configure SSH access on something so you understand how that works). I've had to do this plenty of times with my pfsense box, and as a relative noob to these things as well, having to use nano and vim for editing pfsense configs to revive my server.....it's fucking horrible (sorry vim enjoyers). The good news is, you learn the hard way, but you learn. Try not to have this happen to you, or you'll be back here soon. Once you've had a lot more experience with your tinkering, this will seem less daunting and you'll be more comfortable debugging directly on your laptop server screen.

TrueNAS Scale, as the name implies, is better suited for when you want to include NAS Capatbilities on your setup. Since you mention things meant for Plex/Jellyfin setups, I'd say you could start there.

However you do mention a laptop, so I'm imagining a very basic setup where you probably have limited space or a couple of USB drives or something. You could, instead, opt for Proxmox. You lose the specific capabilities of creating complex RAID setups that TrueNAS would give you, but it sounds like you wouldn't be needing those anyways, as they better fit a setup where you have a bunch of disks connected through SATA or PCIe interfaces. Proxmox is a lot more specialized for containers and VMs so it's probably a good tool to get acquainted with, and might be better suited for a setup where you have just the laptop and maybe a couple of drives to toy around with.

Whichever you choose, make sure to watch YouTube videos about it, read the docs, truly understand what's going on with that tool first, as well as how to set it up correctly. This will introduce networking concepts to you in the process, as you'll need to understand how to access the computer through the network with a browser, as well as with SSH. Make sure you don't ignore networking knowledge. It might seem daunting, or skippable (why bother with local domain names when you can just use the IP and port number?), but a lot of networking concepts are actually rather simple to follow, take a moment on the first few tries but become very easy to reproduce afterwards, and it will make your life easier (yeah turns out, now there's 20 services and you forgot what ports are for what service...if only you had dedicated time to telling the network that port 69420 was for radarr.localdomain and port 42069 was for sonarr.localdomain).

I'd check out Lawrence Systems on YouTube. They make videos covering networking configs with pfsense and the like, as well as TrueNAS configs, and maybe they've delved on Proxmox? Craft Computing, another YouTube channel, for sure teaches about Proxmox. There's tons of video guides for *arr services, I haven't looked for platform-specific configs, but I'm sure you can find both videos for Proxmox and TrueNAS Scale configs. Once you get your first one, most other *arr services are very similarly configured (though not all are, some are very quirky).

Another thing you'll need to understand is how containers work, as well as how to map things from outside the containers into them. Containers are, well, contained, and mappings are how you expose parts of the container to the outside. You'll probably be guided to map things such as your data and the service's config files from outside the container to better organize and persist those things. Make sure you understand this concept, where things are on your setup, where they're getting mapped to in the container, and what this means when it comes to modifying the container (hint: it means you can delete or upgrade the container and things still work exactly as you configured them once your container is back up).

Maybe a controversial advice, but I'd steer clear of the console unless it can't be helped, since you honestly can do a lot from the UI for the vast majority of things you'll need to do. If you DO need to use the console, however, I'd bother ChatGPT and documentation for whatever youre doing, to make sure you understand what every command you try does. Things like "sudo mkdir xyz" should be crystal clear to you. In the case of this failed command, for instance, you should be aware that mkdir doesn't create entire paths, but rather only specific folders. If the preceding folder doesn't exist, the command fails, so if /home doesn't exist, nothing else will work. If /home/user doesn't exist, you're not going to be creating /jackett_config, and so on. Sudo is also a very powerful keyword, which means whatever follows it is an order from the big boss and must be obeyed. As such, absolutely make sure you understand any command that starts with "sudo", as those are the ones that can easily set fire to your entire config. If you don't understand what it's doing, don't run it.

While we are on the subject of folder structures, theres no shame in looking up videos and docs explaining the Unix file structure. If youre coming from windows, this is a veeeeery easily confusing bit, and understanding where you are is very helpful.

Hopefully some of my ramblings make sense to you. Hit me up, or hit the community up, if you need more specific guidance. Things can seem daunting at first, especially if you're new to Unix, but I promise you it becomes easier as you build good foundational knowledge.