A very common membrane type matrix keypad. 3 across and 4 down for 12 buttons in all.
Dupont type connector will plug onto standard 2.54mm (0.1 inch) PCB headers.
Pinout from the left is Row 1, 2, 3, 4 and then Col 1, 2, 3
Self adhesive backing if you want to use that, peel and stick.
Teaching you how to write Arduino code to poll a keyboard matrix is beyond the scope of this sale, but Google will give you all the help you could desire. In short, begin with all pins set to INPUT_PULLUP, now for row #1 pin set it OUTPUT LOW and for each column pin see if digitalRead gives a LOW meaning the button was pressed at Row-Column intersection, or HIGH meaning it wasn’t, put the row #1 pin back to INPUT_PULLUP and move onto row #2 and so forth.
