This is the most difficult part of the lecture. But if you explain it on your fingers, Tor allows a person to hide himself from everyone, including hackers and government surveillance systems that exist in almost any country.
Your signal is passed through three random nodes.
The first one is incoming, let’s say, in Mexico. Anyone can own it. He sees where you come from and roughly understands who you are. But he can’t track what you do afterwards. Because your signal is transmitted to an intermediate node, which may be located in another country, for example, in the Netherlands. What is happening there is not clear at all. But the most interesting node is the third one. Its owner sees where you go, but does not know who you are. Because the signal, that is, your network address, was encrypted twice: on the incoming and intermediate node.
This is how the developers of the system learned to hide users. Three random people around the world can’t give you away, even if they want to.