Occupancy Hour First: Schedule of occupancy for the building. This defines what time the building is expected to be predominantly occupied.
Occupancy Hour Last: Schedule of occupancy for the building. This defines what time the building is expected to be predominantly un- occupied.
As an example, if an office building is being modeled, that is operational from 8am-6pm, the Occupancy Hour First would be 8am and the Occupancy Hour Last would be 6pm.
The occupancy hours are assumed to be at 100% capacity for the hours mentioned in 'Occupancy Hour First' and 'Occupancy Hour Last' for the lighting, equipment and occupancy calculations. To convert the typical fractional schedule into cove.tool format, check out this article.