How does Internet routing work?

Question

Computer networks

Hello, I want to ask a question to knowledgeable people, the essence of the question is this:
We have an Internet provider who gave me a white address, but we also know that the computer, laptop and phone connected to my router have gray addresses, how does addressing work if I I want to send a file to a computer via the Internet, I know about NAT, the question is how exactly the router to which the packet arrives understands which of all the devices connected to it the packet is addressed to.

Answer 1

It is thanks to NAT that he knows.

Along with the source/destination addresses, the source and destination port numbers can also be replaced.
When receiving a packet from the local computer, the router looks at the destination IP address. If it is a local address, then the packet is forwarded to another local computer. If not, then the packet must be sent out to the Internet. But after all, the return address in the packet indicates the local address of the computer, which will not be accessible from the Internet. Therefore, the router "on the fly" translates (replaces) the return IP address of the packet to its external (visible from the Internet) IP address and changes the port number (to distinguish between response packets addressed to different local computers). The combination needed for reverse substitution, the router stores in its temporary table. Some time after the client and server finish exchanging packets, the router will delete the entry about the nth port in its table for the statute of limitations.

https://ru.wikipedia.org/wiki/NAT#%D0%9F%D1%80%D0%...

Answer 2

Okay, Google
Olifer and Olifer Computer networks
The book is just for those who know nothing

Answer 3

https://linkmeup.ru/sdsm/
read until understanding