I really don't understand this, what is a copyright notice [?]
The copyright notice is the notice given by the original authors and/or copyright holders.
Written to give anyone (potentially including you) notice about the copyright.
See as well the dictionary or encyclopedia of your choice.
If you're concerned about legal matters, contact a lawyer on your behalf, they should be able to educate you about the international meaning as well about the differences that apply to you as human locally where you are.
where I should include it?
Please read the sentence again:
It is written there all verbatim.
If you're concerned about the legal meaning of any of these words incl. "included" please contact a lawyer on your behalf. Lawyers are normally educated well enough that they next to legal matters can also help with reading texts as they need to do that a lot.
If you're still in education, another idea might be to talk with your tutor or professor about how to understand sentences like these.
Also the Bootstraps' project did made this as an FAQ, so the information you can find on that page is meant to make it easier for you - not more complicated.