I'm also pretty new to Linux, but I've finally gotten a bit of a grasp on it. I started learning Linux to set up a home server, so I also jumped straight into Docker. You have gotten some thorough replies, but I thought I'd share my chaotic journey with it that has ended in a decent ratio of success vs confusion. Note: I have used Ubuntu from the start.

Don't use docker desktop. It's garbage. Also, don't use the Snap image.

$sudo apt install docker.io

$sudo apt install docker-compose

Those are both cli "programs". They aren't apps like you have on Windows. It seems VERY intimidating to talk into the void of the terminal, but you'll build confidence. Docker commands work like any other commands, all in the same place.

Now install Portainer CE. The instructions are very simple to follow. You can reach Portainer through your browser at the localhost address it gives you, which you type directly into the URL bar. I think it's http://localhost:9000.

Portainer will give you an easy visual way to manage Docker. You can perform many tasks through Portainer instead of using the command line. Honestly, I'm pretty sure you could do everything on Portainer and not even touch the terminal. I don't suggest that because you will have to have at least a basic understanding of how Linux and Docker work. You will be confused, and you will feel crazy. Eventually, you'll get more comfortable living in that psychosis.

On to Docker Compose!! This is my preferred way to run containers. I have a designated folder in /opt that I use for my compose files. This way, I know exactly how I set up my programs. My memory is awful and I tweak things so often that I'll completely forget how I have even gotten to this point or where ANY of my files are. It's pretty easy to find docker compose files online that you can copy and paste and it instantly works!

To make it simple, after I have saved my docker-compose.yaml file in the designated folder, I right click on the empty area and choose "open in terminal".

$sudo docker-compose up -d

The -d instructs the program to continue to run, even if you exit out of the terminal. At this point, your container will also show up in portainer!

I think that covers the basics. My biggest tip is to keep a notepad handy to write down commands that you have to search for. Your bookmarks will fill up very quickly otherwise. Expect to get stuck sometimes. Expect to spend hours trying to troubleshoot an issue, then have it suddenly work with no idea what you actually did to fix it. Accept the win and never touch it again.

I have done fresh installs many times. Some because I've played with 10 different programs that I decided against and want the leftover files gone, some because I wanted to try different mixes of distros, and once because I legitimately broke the OS.

Keep your important stuff on an external drive to avoid any loss and don't be afraid to mess around with it!

Btw, I'm a huge KDE plasma fan. It's lighter than GNOME, but very user friendly. I've settled on Kubuntu as my distro of choice.