The API Guide has it all wrong (really Google?). With Maps API v2 you do not need to enable a layer to show yourself, there is a simple call to the GoogleMaps instance you created with your map.
The actual documentation that Google provides gives you your answer. You just need to
// map is a GoogleMap object
map.isMyLocationEnabled = true
// map is a GoogleMap object
map.setMyLocationEnabled(true);
and watch the magic happen.
Just make sure that you have location permission and requested it at runtime on API Level 23 (M) or above