The radio and mounting kit look good, but the adapter you got uses connectors that aren't on the head unit that you ordered. You can get something like this that just has a connector and some wires, or you can cut off the Honda connector from the adapter you ordered.

You'll connect the connector for the new head unit to the Honda adapter using the pinout diagram for the element radio and the wiring diagram for the radio on page 40 of the manual.

You'll also need an antenna adapter if you want to listen to the radio, so just look up "Honda element antenna adapter" and you'll find them