Ok, First, nothing works.
App has bugs, can't find either RC nor spark (even if I can find them and link them to the phone using wifi).
Then I gave up and went directly to the RC.  Pressed Spark power button for 3 sec, listened to the beep, then pressed the buttons in the RC, light went green, right?  Not really. After that, the light just stayed green, but couldn't fly spark.
I spent hours in tutorials yesterday, fist, trying to make it work like I wanted:  my android Pixel connected to the RC and spark flying, till I removed the phone from the equation and still nothing works.
I'm thinking about returning it, but would prefer it worked.  Can you help?

thank you

Yes, read the quick start guide and the user manual: https://www.dji.com/spark/info#downloads

1๊ี.you be change mobile wifi to connect RC ( remote controller )

Hi, Sam. What is the model of your device? Please try to use another device to search the wifi of your spark or RC. Or you can try to reset the wifi.