how do u determine the spoons, forks, knives are silver?

If they are silver they will have a hallmark, aseries of letters or symbols, somewhere on the piece

Get a hallmarks book so you can check that they are authentic, and not just any old stamp in the metal.
A hallmark is like an artist's signature, and the better ones are listed in books.

This may or may not be helpful, but my grandma showed me that the common stainless forks, knives, and spoons, when gently tapped together in the air, make a clanging noise; the silver, however, makes a distinct musical ring.
She hunts at yard sales sometimes for true silver, which my grandpa then flattens and forms into neat wind chimes!
So, in case you see no mark, there's a clue. :)

hallmark

somewhere on the utencil there should be a marking identifying it as sterling. Also if it tarnishes over time, it's silver!