Please help me. Here is my problem
I have a public internet access in my building. Using one notebook to connect is easy. Just scan and connect. But how about if I have 3 notebooks which I want them all connect to each other (LAN) and they can all connect to the public internet at the same time.
What should I do? Do I need a Router or something call Access Point? I am thinking Router is not enough because the WAN part must be connected using cable.
Unless you have a cable modem in your apartment (usually a small box with screw fit terminal and flashing LEDs) chances are the system in your building uses a router centrally already. Whether you can connect laptops in your apartment to each other via the (theoretical) router depends upon how it is set up.
You may need to add a Router (but before buying that you need to know the nature of the service being supplied to your flat)
You really need to speak to whoever set up the system in your building.
But I would start by trying to get a couple of the laptops talking to each other by connecting them via an ethernet cable (crossover version which you will have to specify when purchasing) between their network ports. This requires some knowledge of Windows (such as setting Sharing in the Properties of the folders you wish to share) and following the Add Network Places wizard).
You'll need to master those basics before attempting to link them via any external systems.