What kind of weight is it? A dumbbell, I'm assuming.
Light or heavy in a weight is relative to what you can lift. Could be too light ot could be too heavy depending on your current level of fitness.
I would start with the basics: bicep curls, tricep kickbacks, military/overhead press, bent over rows.
You can check out some books from the library or check around online for exercise demonstrations if you don't know what the exercises are.
Good luck