The installation process for designer moulding depends on the type of material and the specific design. Typically, it involves measuring and cutting the moulding to the desired length, applying adhesive or nails to secure it in place, and then finishing the edges and corners for a seamless look. Some moulding may require additional steps such as sanding, painting, or staining. It is recommended to consult the manufacturer's instructions or hire a professional installer for precise and accurate installation.