Your first 2 Wildwood Ascendancy Points are acquired when you first meet the associated NPC and choose their specialisation.
The next 4 points come from 2 quests from each NPC.
The final 2 points come from defeating the King in the Mists, which will unlock the final 2 points for all three Wildwood Ascendancies. If you do this quest in advance (e.g. through Multiplayer), it will count towards the points even if you aren’t on that stage of the quest.