Excuse me for my rusty English, the best way I have planned is to practice. The problem is that you can analyze it all, which is a less good presence that I try to do better in English
lol - no need to apologize, you do well. I am told English is one of the hardest languages to learn as a second language.
The person is at the product sheet, that I wonder I work with to use that to share the connection to the internet?
A switch allows multiple users to share a network
connection, NOT the Internet. For each computer to have independent access to the Internet, there must be a router. The gateway device (the cable or DSL modem) only allows one network "node" or device to connect to it, typically a computer. That computer is assigned the IP address issued by the ISP - Internet service provider.
As mentioned, that one node can be a computer, or it can be a network as established by a router. A network can be just one computer connected to a router. When a router is used, the router assumes the IP address assigned by the ISP. As I said before, there are only two connections on a router - one goes to the "cloud" or Internet side, the other side is your network. When you connect your computer to the router, it assigns a new IP address to the computer (a great security measure).
To establish a network of multiple computers, you need a switch, typically a 4 or 8-port Ethernet switch. The switch can be a separate network device, or it can be integrated with the router, such as the very common, Linksys
(note in the image it says, "Router with 4-Port Switch"). The router then assigns new, unique IP addresses to each computer on your
network, but the Internet sees the activity as coming from just one IP address - the one issued by the ISP.
Hope that helps.