Begin by removing all trim that touches the vinyl roof and masking off both the car's windows and painted sheetmetal unless you like cleaning glue off of your new paint job. The masking needs to come right up to the outside edge of the chrome and detail trim lines. The roof has been primer prepped, and the new vinyl is sun-treated. Use a tape measure and a Sharpie to place two marks, one at the front and one at the rear, on the exact center of the roof for proper alignment. This is a critical measurement; double-check it before going any further.