Not sure if there is something I need to do as I'm new to dji drones.  When I push the physical RTH button on the controller it does not do anything.  Do I need to hold the button down or something?  Didn't want to risk just pushing buttons as afraid I might activate another setting.  

If you're attempting to initiate RTH, you need to press and hold the RTH button for a few seconds (until the remote controller starts beeping). If your Spark is RTHing, you can quickly press and release the RTH button to cancel RTH.

Ok, Great.  Thank You

Thanks for msinger's help. You can also check the relative info on the manual. Besides, I suggest learning the RTH procedure, too. If more info needed, here is the link to the manual.