Where to place the button to open a DataTable and fill input fields based on selection?

I have a wizard that has four steps. On the first step, there is a form with user data inputs. I need to have a button that opens up a modal with a datatable, and based on the selection on that table, the input fields to be filled with that information. But I am not sure where to place this button and what design would be best to use so that it looks good. This is what it looks like thus far :