Android Question Change the app's icon

Hi, how can i change the icon of the app / apk to one of my own

I choose Project / Choose Icon and select the icon I want, 72 x 72 png file but the program states it can't access the path I have tried to save my icon to the drawable path and tried in in files folder but still get the same error and the icon reverts back to the green android icon, tried looking on the forum but getting nowehere. many thanks