How do sand dunes move

Sand dunes are masses of loose sand that move across the ground in wind. The grains are blown up the windward side of a dune until they reach the top; then they drop down into the shelter of the lee (the side away from the wind). Other grains are blown up and over, burying the first.

Mostly because of the wind outside and inside the loose sand. It blows the windward and makes it get to the top. Just the wind though