Convert string to time xcode

I have a json containing various times. Like below

{ "5:10" "14:24" } I need to use this time to fire local notification everyday.

Can u please suggest me how to properly put this string in this line.

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *now = [NSDate date];
NSDateComponents *componentsForFireDate = [calendar components:(NSYearCalendarUnit |   NSHourCalendarUnit | NSMinuteCalendarUnit| NSSecondCalendarUnit | NSWeekdayCalendarUnit) fromDate: now];
[componentsForFireDate setHour: 20] ;
[componentsForFireDate setMinute:0] ;
[componentsForFireDate setSecond:0] ;

NSDate *fireDateOfNotification = [calendar dateFromComponents: componentsForFireDate];
UILocalNotification *notification = [[UILocalNotification alloc]  init] ;
notification.fireDate = fireDateOfNotification ;
notification.timeZone = [NSTimeZone localTimeZone] ;
notification.alertBody = [NSString stringWithFormat: @"New updates!"] ;
notification.userInfo= [NSDictionary dictionaryWithObject:[NSString stringWithFormat:@"New updates added for that week!"] forKey:@"new"];
notification.repeatInterval= NSDayCalendarUnit ;
notification.soundName=UILocalNotificationDefaultSoundName;

NSLog(@"notification: %@",notification);
[[UIApplication sharedApplication] scheduleLocalNotification:notification] ;

In this code i am manually adding the time to 8 pm. I need to put that time from json into the code.

Thanks in advance.