I ask you: How to add controls to adjust the level of xcode

I have two buttons, adding that the total after adding the above earlier, but I wanted him to do a cover button below, how to solve? Thank you
Reply:
- (Void) bringSubviewToFront: (UIView *) view;
- (Void) sendSubviewToBack: (UIView *) view;

Reply:
Use the mouse to drag the view corresponds to the list below.
Eg: display view,
label1,
label2.
To get the upper label1, drag the label1 label2 below it. (Yesterday, the Lions tried in the system).
Reply:
- (Void) bringSubviewToFront: (UIView *) view;
- (Void) sendSubviewToBack: (UIView *) view;
Reply:
Direct attempts to drag the view on button 2, it will not cover
Reply:
1st Floor positive solution.
Reply:
More sophisticated method to change the view hierarchy:

- (Void) insertSubview: (UIView *) view belowSubview: (UIView *) siblingSubview;
- (Void) insertSubview: (UIView *) view aboveSubview: (UIView *) siblingSubview;

- (Void) insertSubview: (UIView *) view atIndex: (NSInteger) index;
- (Void) exchangeSubviewAtIndex: (NSInteger) index1 withSubviewAtIndex: (NSInteger) index2;