Dusty Dune Galaxy is accessible from the Bedroom observation dome. You need 29 Stars to enter.
Star 1: Soaring on the Desert Winds
In this star, tornadoes are all around the galaxy.
First Part: Fly to a green pipe. When your under ground, walk through a long hallway. At the end of the hall, use a sling star to reach another green pipe. The checkpoint is right by a launch star.
Second Part: Climb a tornado tower to get the power star. Then your done with the first power star for this galaxy.
Star 2: Blasting through the Sand
There is a Hidden Star on this level. For the time being, do not feed the Hungry Luma.
Star 3: Sunbaked Sand Castle
There is a Hidden Star on this level. Do not collect any musical notes you may find.
Star 4 (Speedy Comet): Sandblast Speed Run
This Star is available when a Prankster Comet is in this Galaxy.
Do the same as for Star 2, only within a 4 minutes and 30 seconds time limit. There are no tornadoes.
Star 5 (Purple Comet): Purple Coins in the Desert
This Star is available when a Purple Comet is in this Galaxy.
Star 6 (Hidden): Bullet Bill on Your Back
Enter Star 3 and take the same path that you took for that Star until you reach the planet with the spiky plant. If you don't see it at first, it's most likely because the sand has covered it. Wait a moment until the sand recedes and then Ground Pound the tree stump and collect all the musical notes that appear. Use the Launch Star to reach a new planet.
Star 7 (Hidden Green): Treasure of the Pyramid
This is one of the three Green Stars, which you need to collect to unlock the Trial Galaxies.
Enter Star 2. Feed the Hungry Luma 20 Star Bits.