Set up an ICE problem (Initial, Change, Equilibrium) in order to use the Ksp value to calculate the concentration of each of the ions. The concentration of the ions leads to the molar solubility of the compound. Use the molar mass to convert from molar solubility to solubility.
Does lower KSP mean lower molar solubility?
The value of the constant identifies the degree to which the compound can dissociate in water. The higher the Ksp, the more soluble the compound is.