There are six Place of Power in the first “Map”: White Orchard. You need to draw power from the five that I marked in red. Every buff holds for 30min, so you need to visit them all in that timeframe. The yellow on is a duplicate but visited it too, you get an Ability Point from every Place of Power.
There are six in White Orchard, eight in Velen (one inside the Cave at the Magic Lamp Side Quest, one accessible later in the Story) and nine in Skellige (One you find later that King’s Gabmit Main Quest). The two later in Act 3 in the Trough Time and Space Mission and Battle Preparation.