I feel you. I was where you are 2 years ago and it was really hard to start off.
I'd suggest starting installing Debian as an OS. Then, go for Docker.
If you feel lost, you can take a look at some videos from DBTech on YouTube. Look at his playlists to sort what you need.
Remember to document everything you do, because you'll forget what you did to make things work your way.
Have fun !
I think Vikunja can do all that.