Present view controller using Storyboards - ios

Question

I have followed a tutorial to add In App Purchases to my app. There are 2 views:
Button to 'Buy item'
Screen comes up that allows user to select product
I have added the code completely fine but in the tutorial they were using XIB files but I am using Storyboard. My code for the 'Buy item' button looks something like this:
- (IBAction)PurchaseItem:(id)sender {
_purchaseController = [[PurchasedViewController alloc] initWithNibName:Nil bundle:nil];
_purchaseController.productID = #"com.myapp";
[self presentViewController:_purchaseController animated:YES completion:NULL];
[_purchaseController getProductID:self];
}
The issue I have is that when the button is clicked, a black screen appears, but I want PurchasedViewController to show
Do I need to change something?
EDIT:
Using edited code but getting error as attached:
- (IBAction)PurchaseItem:(id)sender {
PurchasedViewController *purchaseContr = (PurchasedViewController *)[self.storyboard instantiateViewControllerWithIdentifier:#"menu"];
//menu is only an example
purchaseContr.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentViewController:purchaseContr animated:YES completion:nil];
}

Answer 1

With a storyboard you should give an Identifier like in the picture:
tap on your viewController and in 'identity inspector'
in this example Custom Class should be: PurchasedViewController
and this is the code:
- (IBAction)PurchaseItem:(id)sender {
PurchasedViewController *purchaseContr = (PurchasedViewController *)[self.storyboard instantiateViewControllerWithIdentifier:#"menu"];
//menu is only an example
purchaseContr.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentViewController:purchaseContr animated:YES completion:nil];
}

Answer 2

Try this
_purchaseController = [[PurchasedViewController alloc] init];
_purchaseController.productID = #"com.myapp";
/* 1. Add the new VC as a child VC */
[self addChildViewController:_purchaseController];
/* 2. Add new view to source view */
[self.view addSubview:_purchaseController.view];
/* 3. Inform 'didMoveToParentViewController' to newly added view controller */
[_purchaseController didMoveToParentViewController:self];
[_purchaseController getProductID:self];