I can tell you what the instructions are but it depends of course on the temperature of the room, and the must (grape juice and berries) when they start to ferment. And the type of grapes and yeast. All this is in Celsius:
YEAST
Put yeast food into hot water 43 degrees C
Allow mixture to cool to 40 degrees C
Add yeast and stir
Let yeast sit at least 15 min no more than 30 min
Take temperature of the yeast / water
Slowly add grape juice to lower the temperature by 10 degrees C
Wait 15 min
Slowly add grape juice to again lower temp by 10 degrees C
Take temperature
That's what is going on here. The small buckets contain the yeast, water and juice mixtures and each vat gets its own infusion, temperature check, stirring, etc. This is just the first batch of grapes from California's Sierra Foothills ... next week twice as much will be arriving from Washington State.

When yeast and juice are within 10 degrees C of the vat temperature, add the mixture to the top of the vat (I think these vats are about 18-22 degrees)
Do not stir for at least 12 hours. Then stir mixture for 5 minutes every 6 hours for 4 days
After Stir mixture for 5 minutes every 8 hours for 3 days.
As the fermentation continues the vat will get hotter and hotter. At some points it may need to be cooled down.
Of course, in the middle of this process, when the covers are off, people are taking out the stems, leaves and other things that don't belong in the wine.
The temperature of the mixture during fermentation will vary with the room temperature, volume of juice, intensity of fermentation, etc.
Cazalea