We gladly give instructions on how to do it. It is easier to tell you what not to do. DO NOT use abrasives like scouring powders. It will take away the shine and over a period of time dull the surface. Liquid cleaners like Mr. Clean, Dupont 409, or Dow Foaming cleanser are good for this product.
Cultured marble is sealed with mildew proof silicon.
Silicon dries to a rubber and will not normally crack. It for some reason the silicon comes out of a joint, it should be replaced right away. It is a simple process that homeowners can do.