The Internet is simply a huge, global computer network. In order to connect to the Internet, you need to be wired into that network.
Most people use a modem to dial into another computer connected to the Internet.
The connection at the library travels through a high speed ISDN line. You will need to have an account with an Internet provider for Internet access. The Internet has many different functions. The most popular Internet segment is the World Wide Web. What you will be using here is primarily the World Wide Web.