here is the hint ... think in reverse. imagine the goal then step backwards. ask yourself "what do i need to make this happen?" then step backwards .... and so on ... does that help or is it a spoil?
Use one white star to hit one of the blue so it moves away. Move white ones so they block one of the blue from being pushed away. Then move the blue one in with the rest.
vidagrrl, notice the "regular stars" exactly above the North Star? Can you use them to line up a "supportive column", so you can complete the North Star from b elow?... Hope, that's not to much spoilers...