Make a link that will add the text into another text box with other info

Make a link that will add the text into another text box with other info

  
Here is what I am doing. Someone can go into the create a new pawn. Once they do that, at the top, there is a Customers List that displays Customers already added. As well there is a search box where they can search that list. What I am wanting to do is to have them able to add the name and another field to the bottom corrosping boxs if they click on a box to the side (or if they clicked on the name). I have attached the project file that I am working on (though right now the add button links to (current screen)).
NOTE: The page I am working in is Pawn_Edit
As well if you happen to see why that search box isn't working, could you tell me why. All of this is under the Pawn_Edit page.