In this app you only need to connect smart TV and mobile phone with the same WIFI and then go to select TV option in your mobile app and there will be 3 dots at the top right corner press it and press the (enable wireless display) and connect it with your TV.

NOTE:

This App runs perfectly on devices, you can be tested on Samsung, HTC, Sony mobile phones, and Some devices don't support cast mirroring screen and maybe this Miracast HD Video screen mirroring TV app will not work, only this HD video screen mirroring app support all android phone from 4.5 above.