It/second and loss function

I have 3 questions:

  1. What does it/second denote when the model is getting trained?
  2. How to change the loss function manually?
  3. Is the submission format for all Kaggle datsets similar to what was explained in Lesson3?
  1. iterations per second
  2. what do you mean? Change the function type?
  3. you’ll find that info in the “submission” section of the competition you choose.