[Effendi]

SMS = short message system
The SMS is just a message (max 160 letters) which you can send from your phone or usb dongle to another number. The one who receives your SMS will see your number, so that's how you are recognized by the automatic service for activating option. Your number is linked to the sim-card, not to the phone/usb dongle.

In order to use a data offer like the Internet 40 (which is a horrible option, by the way) you have first to buy a prepaid sim card (10€, including 5€ of credit), then you have to refill it in order to have sufficient credit on it to activate the data offer you chose.

You can send the activation SMS from the program which your usb dongle will install/have installed on your laptop. But you can also ask the dealer which sold you the simcard to do it for you. But it's really an easy thing to do.

In any case I'd go with some better option such as Internet No Stop by Wind or Web 1 GIGA by COOP Voce if you prefer to use TIM network.