It was real easy. Just remove the one hex bolt and lift up the dash panel. There is a slot already in the panel for the hour meter. Use a knife or razor blade to cut out the vinyl covering over the slot. Then you can snap in the hour meter. No screws required.
There are two wires with female sockets already in your mower, right beneath the dash panel. Just lift them up and plug them into your new hour meter.
I didn't have any instructions but it was simple enough I could figure it out once I looked at the hour meter and existing wiring.