Drywall installation involves hanging large sheets of gypsum board on walls and ceilings to create a smooth surface for painting or finishing. The process typically starts with measuring and cutting the drywall to fit the designated areas. Once cut, the sheets are secured to the framing using screws or nails. After the drywall is installed, the seams between the sheets are taped and covered with joint compound to create a seamless appearance. Once the compound dries, it is sanded down to achieve a smooth finish. Finally, the surface can be painted or decorated as desired.