Nano Usb Adapter not working

hi
i'm senior and i started learning raspberry pi 2 for my graduation project
i did the basic netwok setup using wierless home
but i must use usb adapter for my project so i make connection and plug usb adapter in raspberry pi but it's not shown any reaction
can any one tell me how make it lighting up so i can then install drivers and all stuff i need ?
sorry about my En
Thx