How do I tell what model of Rolex I have?

I just inherited a Rolex watch from my grandfather but it doesn't fit me, So how do i find out what model it is to see they offer extension links for it. I would really like to be able to wear it,|||That's nice.You can go to your nearest LEGIT jewelry store(that sells legit Rolexes) and ask or you can go to the Rolex website and browse through the designs.good luck