How to connect a Microphone to your phone
The Rode Mic worked great for me
Hot to make it work for you
This is what you get plus the windsock. but you need a converter for your phone to recognize the plug as a microphone not headphones. Is called a TRS to TRRS Patch Cable and what this does is just routing the connections where they supposed to go.
And a bracket or mount for the mic separately from the phone because the mic weight would be too much for the gimbal of the Osmo. And I did a small video how to help the osmo to deal with an Plus size phone. https://youtu.be/pJ8eDhXfmMI