Brewing a Bierce de Garde

Hello I am going to brew this Bierce de Garde from an BYO article. But my ? Is the fermentation it said too Start fermentation around 66 °F (19 °C) and then raise the temperature a few degrees more (70 °F/21 °C) several days into active fermentation. Now the part that saids raise fermantion temp several days into active fermentation now how many days is the several going to be in a active fermentation meeting is it 2days, 3days, etc before I start raise the temp?

That’s why they say a few it’s not that critical. Just wait till it slows down a bit