Generally most people will have an idea of which finish is suitable for the area that needs to be coated. For further guidance on what goes where, please refer to specific products and datasheets where you will find detailed information on all of the products in the Dulux Trade and Glidden Trade ranges.
Each section will has product selection guides which detail whether a product can be used internally or externally, which substrate(s) it can be applied to, what primers are suitable for particular surfaces and also contains links to the product information sheets and product data sheets.