Copy an Entity With Navigation Property in C#
It appears that _equipments.AsNoTracking().FirstOrDefault gets some objects that have a unique ID  

When you _uow.MarkAsAdded(newAsset, _userManager.GetCurrentUserId()); that collection requires unique ID. You go through round about way to to create a new ID so that you don't get a conflict.  

Same thing for both Asset ID and Schedule ID.  

All this is doing is assign a new unique ID.  

Schedule newSchedule = new Schedule();
Guid scheduleId = newSchedule.Id;
newSchedule = row;
newSchedule.Id = scheduleId; 


newSchedule is a reference to row so  newSchedule.Id = scheduleId; is just assigning a new ID to row  

It someone is reading that different please comment.  

It appears you changing code to get rid of error messages without fully understanding the code and objectives.