IPhone : How to move or navigate from .mm file to .m file

I have little proble with .mm file. i have to navigate .mm file to .m file but i can't navigate .m file. any one knows how to move it.

Example:-

AlarmViewController *objAlarmViewController =[[AlarmViewController alloc]initWithNibName:@"AlarmViewController" bundle:nil];
[self.navigationController pushViewController:objAlarmViewController animated:YES];

I am trying to do this code in .mm file but i can't move to .m file. & i got one error regarding uinavigationcontroller.(error: Property 'navigationcontroller' not found on object of type 'ABCViewcontroller*')

Note:- I am not asking to change file extention .mm to .m file. i just want to navigate from .mm file to .m file.