Insert data in uitable from textbox

Hi i’m working on program depends on inserting two numbers into two text boxes. When I press the pushbutton, the two numbers are combined and displayed in the first row of the table. When I enter two other numbers in the text boxes and press the pushbutton again, the new resolt is displayed in the second row of the table and etc. But the problem is that the new resolt replaces the old resolt in the first row What’s the code that allow me to set data in second row then thired etc....