You should aim to bring your baby along when they are at their best so have napped and eaten – though babies are notorious for changing their schedule just when you think you’ve got it nailed.  Quite often that means that a start time of 10 or 11 is ideal and after lunch and afternoon nap means the afternoon sessions start at 2pm and 3pm.  That said, there’s no fixed start time as far as I’m concerned – just whenever is best for you and your little one.