OK, here is how I use the PlayMemories Mobile app from my Note8 Android smart phone...
- Install "PlayMemories Mobile" app on your phone (my iPhone is the same way)
- Make sure your WIFI is on, and any WIFI networks disconnected from (you want WIFI on, but not be connected to any networks)
- On your a7R3, go to "Menu", go to tab that looks like a globe, called "Network1" tab 1/2
- Arrow down to "Ctl w/ Smartphone", and select (using the select button in the middle of grooved turn dial on back that has DISP, ISO, etc, it's the middle button)
- Make sure "Ctrl w/ Smartphone" is "On" (if not, select "Off" and set to "On")
- Next, scroll down to "Connection" and select (this will put the camera in a WIFI mode and present you with a "Connection Info" screen, which contains a QR code.
- Now, on your SmartPhone, open the PlayMemories Mobile app and select "Scan QA Code of the Camera"
- hold your phones camera up to the back of the a7R3 until it vibrates and says "Scanning Complete"
- Select "OK" to Connect with the camera?
- WHALLAH!!!
Hope that helps