A DayFormat is a grid with 24 slots, one for each hour of the day. You click the clocks you want to use into the hour slots. You have a DayFormat for each day of the week. One Dayformat may be used on multiple days of the week. Most common is to have one Dayformat for Saturday, one for Sunday and one for the five Weekdays. Some stations do have a unique Dayformat for each day of the week. Here's a video showing how to put it together.