Change Container View Content with Tabs in iOS

I'm trying to make a form that spans three tabs. You can see in the screenshot below where the tabs will be. When the user taps a tab, the Container View should update and show a particular view controller I have.

Tab 1 = View Controller 1

Tab 2 = View Controller 2

Tab 3 = View Controller 3

The view controller shown above has the class PPAddEntryViewController.m. I created an outlet for the Container view within this class and now have a Container View property:

@property (weak, nonatomic) IBOutlet UIView *container;

I also have my IBActions for my tabs ready:

- (IBAction)tab1:(id)sender {
  //...
}
- (IBAction)tab2:(id)sender {
  //...
}
- (IBAction)tab3:(id)sender {
  //...
}

How do I set the container in those IBActions to change the view controller that the Container View holds?

Among a few other things, here's what I've tried:

UIViewController *viewController1 = [self.storyboard instantiateViewControllerWithIdentifier:@"vc1"];
_container.view = viewController1;

...but it doesn't work. Thanks in advance.

I recently found the perfect sample code for what I was trying to do. It includes the Storyboard implementation and all the relevant segues and code. It was really helpful.

https://github.com/mhaddl/MHCustomTabBarController