You need to explore UILocalNotification, using which you can set notification at particular interval and also it is possible to set custom sound, see this example for custom sound, files for your app.
like
UILocalNotification *notif = [[UILocalNotification alloc] init];
NSDateComponents *dateComp = [[NSDateComponents alloc] init];
[dateComp setDay:YourDay];
[dateComp setHour:YourHour];
[dateComp setMinute:YourMinute];
NSLog(@"Year: %i, Month: %i, Day: %i, Time:%i:%i\n",[dateComp year], [dateComp month],
[dateComp day], [dateComp hour], [dateComp minute]);
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
notif.fireDate = [gregorian dateFromComponents:dateComp];
notif.timeZone = [NSTimeZone defaultTimeZone];
notif.alertBody = YourAlertBody;
notif.soundName = @"fireburn.caf";
Note : Above code credit goes to this question