NSOperationQueue block updates UI before previous task finishes

Question

I need to complete following tasks in order and update UI after all the task are completed. Since data is depended on each other I have created NSOperationQueue *myQueue but one of the tasks taking so long to complete meanwhile last task is not waiting for previous task to finish and just updating the UI

Task order should be
1.Show Loading hub
2.Parse html get ids
3.Download Json with the parsed ids
4.populate database with json
4.1 This part also has a lot of background work populating database takes about 5-6 seconds.
5.Hide loading hub

So 5 is executed before 4 and 4.1 finishes....
basically I want this Serial but this is happening I guess Concurrent I have also tried 'dispatch_sync' no luck

-(void)viewDidAppear:(BOOL)animated
{
    //show hud
    [self performSelectorOnMainThread:@selector(showLoadingHud) withObject:self waitUntilDone:YES];
    [self startProcess];

}

-(void)startProcess
{
    NSOperationQueue *myQueue = [NSOperationQueue mainQueue];
    [myQueue setMaxConcurrentOperationCount:1];

    __block NSMutableArray *imdbIDs=[[NSMutableArray alloc] init];
     NSMutableArray *urlList=[[NSMutableArray alloc] initWithArray:[ImdbURLs getImdburlArray]];

    NSBlockOperation *getiImdbViaHtmlParser = [[NSBlockOperation alloc] init];
    __weak NSBlockOperation *weakHtmlParser = getiImdbViaHtmlParser;

    [weakHtmlParser addExecutionBlock:^{
        //first
        for (NSString *imdbUrl in urlList) {
           ...
    }];

    NSBlockOperation *getJsonFromIMDB = [[NSBlockOperation alloc] init];
    __weak NSBlockOperation *weakGetJsonFromIMDB = getJsonFromIMDB ;

    [weakGetJsonFromIMDB  addExecutionBlock:^{
        //second
        for (NSString *imdbStrings in imdbIDs) {
                //this also calls database methods and populates database with safe threads
                [self AFReqTest:imdbStrings];//I guess this causing the problem
        }
    }];

    NSBlockOperation *checkResult = [[NSBlockOperation alloc] init];
    __weak NSBlockOperation *weakCheckResult = checkResult ;

    [weakCheckResult addExecutionBlock:^{
            //dismiss hud
            [[NSOperationQueue mainQueue] addOperationWithBlock:^{
                [self dismissLoadingHud];//this is getting called before getJsonFromIMDB block finishes
            }];
    }];

    [checkResult addDependency:getJsonFromIMDB];
    [getJsonFromIMDB  addDependency:getiImdbViaHtmlParser];

    [myQueue addOperation:getJsonFromIMDB];
    [myQueue addOperation:getiImdbViaHtmlParser];
    [myQueue addOperation:checkResult];
}

-(void)AFReqTest:(NSString *)idString
{
    ...//buch of code
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {

       //here I call another background method with result 
      [self insertIntoDatabase:responseObject];

    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];

}

-(void)insertIntoDatabase:(NSDictionary *)responseObject
{
    ParseImdbResponse *parse=[[ParseImdbResponse alloc] initWithResponseDic:responseObject];
    PopulateDatabase *inserInstance=[[PopulateDatabase alloc] initWithResponseDic:parse];

    dispatch_queue_t insertqueue= dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoMoviesTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoGenresTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoActorsTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoDirectorsTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoMovieGenresTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoMovieCastTable];
    });

}

Sorry for the long code I am not sure problem is my code structure or am I missing something?