How to deal with linux terminal? What does this command do in detail?

Question

linux

Good afternoon. There is such a command

sudo apt-add-repository -y ppa:brightbox/ruby-ng;
sudo apt-get update;
sudo apt-get -y install curl;
curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -;
sudo apt-get -y install nodejs;
sudo npm i -g gulp rimraf npm-check-updates bower;
sudo chown -R $USER:$(id -gn $USER) /home/$USER/.config

For convenience, I broke it line by line.
Let's start in order.
1) sudo apt-add-repository -y ppa:brightbox/ruby-ng
sudo apt-add-repository turns out to make ruby ​​updated not from the ubuntu repository, but from ppa:brightbox/ruby-ng? I understand correctly? If so, where does he get this package from? Where does it find brightbox ?
PPA is it a package? Just a package that is downloaded?
the -y flag. I found out with the command apt-add-repository --help why it is needed
-y, --yes Assume yes to all queries
That is, the flag says "yes" to all requests? What? How to understand it?
2) sudo apt-get update
apt-get update turns out to update all downloaded packages on the PC. Correctly?
3) sudo apt-get -y install curl
apt-get -y install installs the curl library from the ubuntu repository.
Also the -y flag?
4) curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash is
the curl library command. -sL is the same as -s -L ?
And what does curl actually do? update the path of a repository in the Ubuntu repositories to a specific package?
If you download nodejs via apt-get, then there is an old version, and through curl we change the link to another version, is it? Or how? Why didn't we specify the name of the nodejs package then, but just a link? how does he know what to update from nodejs?
| sudo -E bash - what does this command mean? | is it like "or"? Why is he?
And in general, am I right when I say the ubuntu repository where all the repositories are? How to watch it?
4) sudo apt-get -y install nodejs
Downloads nodejs from the new path, and npm along with it. Right?
5) sudo npm i -g gulp rimraf npm-check-updates bower
Since we have downloaded nodejs, we now have npm available. with it we install packages globally
6) sudo chown -R $USER:$(id -gn $USER) /home/$USER/.config Does
this command change ownership? Why is this needed? How does it work? Explain please ..
I'm just starting to understand linux and please do not throw tomatoes at me. Thank you so much in advance!!!!!!!!