Modal in a storyboard

I have multiple Storyboards in my application. When opening a new storyboard i want to open the storyboard as a modal. That way I can call DismissViewController on the last step of the modal.

Are there any settings I need to set in any of the Storyboards to make this happen. I am opening the "modal" storyboard using NavigationController.pushViewController. I am closing the modal by calling NavigationController.DismissViewController. I have tried using the DismissViewController method on the last step's ViewController, but that didn't work either.

// Open modal NavigationController.PushViewController(signUp, true);

// Pop modal DismissViewController(true, null);