We have installed new granite countertops in our kitchen. I took off the old backsplash but I am wondering what do I need to do to prepare the surface exactly for tile backsplash. The company we hired to install the backsplash just said to remove the old laminate backsplash. I took it off and in some areas, there is still some glue left from the old laminate. Also, in some of it, the sheet rock paper shows(but not all the way down to the gypsum). What exactly do I need to do additionally? Thanks for your comments in advance!