What steps we must follow during a launch of new product to direct customer call?

Well hypothetically it may vary from environment to environment and product to product, however there can be some back ways that can be followed as listed by Forbes...

http://www.forbes.com/sites/theyec/2013/08/26/five-steps-to-a-seamless-product-launch/

YES ITS TRUE THAT PRODUCT, INDUSTRY, ETC PLAYS IMPORTANT ROLE IN DEFINING THESE STEPS BUT THERE ARE CERTAIN FUNDAMENTALS TO MOVE ON.