in mixture of common salt,sand and ammonium chloride first step of separation is :

(1)sedimentation (2)crystallisation
(3)filtration (4)sublimation

The first step should be sublimation as ammonium chloride will sublime to leave the mixture of common salt and sand.
The next step would be sedimentation and decantation.
The sand does not dissolve in water, so can be separated by sedimentation and decantation.
The salt dissolves in water, so it can be separated by evaporation process.