How to iterate the first value and the second value in a list in C#

try
    {
        List<int> taskTypeList = new List<int>();

        var flowBranches = from flow in _db.FlowBranches
                .Where(x => x.FlowID == flowID)
                .Select(x => new { x.FirstTaskTypeID, x.SecondTaskTypeID, x.DependencyType }).ToList()
                           select flow;

        foreach (var item in flowBranches)
        {
            var itemQuery = from y in _db.TaskTypes
                            .Where(x => x.TaskTypeId == item.FirstTaskTypeID)
                            .Select(x => x.TaskTypeId).ToList()
                            select y;

            taskTypeList.AddRange(itemQuery);
        }

        foreach (var taskId in taskTypeList)
        {

            //Do stuff
        }

        return 0;
    }