How to add new order or add new site to an existing customer

Hi Can anyone please assist, I have exhausted all options I can think of to enable the basic function of adding a new order or adding a new site address and then a new order to an existing customer data table, however when I publish the page the "add new site address or “add new order form” appears as a form under the customer list, I would like to be able to click on my existing customer and add the details from there, any advice please, thank you