Issue on the peer review one

I have tried to do the same exact steps on the lecture but I have this code error popup

#import <UIKit/UIKit.h>
#import “AppDelegate.h”

int main(int argc, char * argv[]) {
NSString * appDelegateClassName;
@autoreleasepool {
// Setup code that might create autoreleased objects goes here.
appDelegateClassName = NSStringFromClass([AppDelegate class]);
}
return UIApplicationMain(argc, argv, nil, appDelegateClassName);

}

and this thread,
Thread 1: Exception: “[<ViewController 0x7faa7ee08fa0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key testLabel.”
any help?