Ground plane automatic hit test

Hi,

     Please help how to get callback for Ground plane detected and running by c# script.

     Also we need to launch the object automatically once the ground plane is detected. Instead of user manually click and launch. But we changed in Plane Find Behaviour options as "On Interactive Hit  Test" to "On Automatic Hit Test" but the AR scene launching every where instead of ground only. Please assist on this, i have attached screenshot for your ready reference

Thanks,

Sudhakar.G