UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
With an Identifier:
Give the scene a Storyboard ID within the identity inspector of the storyboard.
Instantiate in code:
UIViewController *controller = [storyboard instantiateViewControllerWithIdentifier:@"myIdentifier"];
Instantiate an initial viewcontroller:
Within the storyboard select the view controller, then select the attribute inspector, check the "Is Initial View Controller" box.
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
UIViewController *controller = [storyboard instantiateInitialViewController];