Once you have chosen the "rate and departure time" hit "settings" and then hit "edit schedule". That will take you to the complicated and frustrating screen where you manually set the times you want the car to consider "peak' "partial" and "off peak". It took me a bit but I finally managed to get it right. (Poorly designed process in my opinion.)
You can then choose when you want the car to charge. I choose "off peak only" or some such since I don't drive much and could safely ignore the warning that it might not charge in time. You have to do summer and winter since the peak times likely change for your utility.
I hope this helps. Good luck.
