Try using IB to see the coordinates at which you want to place your objects, and then add them to the code. Usually you need to make a trial version and make an error so that everything is correct.
. , 480/2. UIScreen :
(, UIView - , iPhone, iPad, iPad)
myView.center = CGPointMake([[UIScreen mainScreen] bounds].size.width/2, [[UIScreen mainScreen] bounds].size.height/2);