Controller in ScrollView extending too far - ios

Question

I'm building a Login Flow with a UIScrollView but I can't figure out why my first view controller (step1VC) is extending further than the screen size. Here are screenshots of the first and second view controllers.
Looks fine on an iPhone 5, but not 6/6 Plus
Code
- (void)viewDidLoad {
[super viewDidLoad];
// Set up Content
CGSize screenSize = [UIScreen mainScreen].bounds.size;
self.contentScrollView.translatesAutoresizingMaskIntoConstraints = NO;
self.contentScrollView.contentSize = CGSizeMake(screenSize.width * 3, screenSize.height);
self.step1VC = [self.storyboard instantiateViewControllerWithIdentifier:#"LoginStep1ViewController"];
[self addChildViewController:self.step1VC];
[self.contentScrollView addSubview:self.step1VC.view];
[self.step1VC didMoveToParentViewController:self];
self.step2VC = [self.storyboard instantiateViewControllerWithIdentifier:#"LoginStep2ViewController"];
self.step2VC.view.x = screenSize.width;
[self addChildViewController:self.step2VC];
[self.contentScrollView addSubview:self.step2VC.view];
[self.step2VC didMoveToParentViewController:self];
self.step3VC = [self.storyboard instantiateViewControllerWithIdentifier:#"LoginStep3ViewController"];
self.step3VC.view.x = screenSize.width * 2;
[self addChildViewController:self.step3VC];
[self.contentScrollView addSubview:self.step3VC.view];
[self.step3VC didMoveToParentViewController:self];
}

Answer 1

You haven't set constraints to views, add constraints to them, for example to make tagline center and full width, pin tagLine label to left and right of superView, same with title and button.
For title and button you can set there width and height and then can pin them horizontallyCeneter in super view.
And if you are using AutoLayout constraints with scrollView then you should know auto layout works bit differently with UIScrollView you can check this answer for this question and apple docs for more details
Tip: Add width constraint to stepVcs.View and set its value to scrollView.frame.width