Replying to Routers

I feel like they might be less complicated than they seem, I know I could just google but I like you guys and want to kill some extra time cause Im bored, but heres the deal. My parents are moving to florida in a week or 2. Im staying with my grandparents so I can keep working before I leave for college. Obviously grandparents being grandparents dont have a router. Would I be able to just plug one into their modem and Ill be set? Or is there more to it? Will I need extra cables?