I did download the one you suggested. Twice. It's just not showing Spark at all. My other anroid device show it in the app. I am going crazy.Guess you'll have to buy an inspire aircraft, I seen one in the classifieds for about $4000.
You may have downloaded the wrong app, the DJI GO.
What you want is the DJI GO4 app (for drones since P4).
Did you turn on your drone and connect via WiFi? When you do it should change to the Spark and you will get the option Go Fly!