A newspaper is a kind of large, unbound book that is printed every day on cheap paper. The newspaper usually has the day's news, advertising, things for sale, the state of the financial markets, sports results and anything else that has happened that is interesting enough to write about.
Paper is usually made from very finely ground up wood, bleached white. Paper is thin, usually smooth, and is used to make books, newspapers, magazines and of course you can buy blank or lined paper to draw or write on. Pieces of paper come in lots of different sizes, textures and colours. Rougher paper is better for drawing on in pencil or charcoal. Paper can be cut or folded into different shapes, for crafts like origami.
Sandpaper, originally called glasspaper, is paper with something rough stuck to one side. Sandpaper is used for removing old paint from things, for making wood or similar surfaces smooth, or for roughening up a surface. There are hundreds of different varieties of sandpaper.