You must obtain 3 stars in the 4 levels of the world 3. Here are the videos of these levels in DUO mode (in these videos, we got 4 stars, but only 3 are necessary for the achievement).
Level 3-1:
Level 3-2:
Level 3-3:
Level 3-4:
The big challenge is the change of strategy and role when the platform moves. But through training, it ends up happening.