Clothing assets in VaM often require specific pose adjustments to prevent feet from clipping through the floor:
If the feet look flat, go to Person -> Morphs and search for "Foot" or "Heel" morphs. High-quality heel sets usually require a "High Heel Pose" morph to be dialed to 100% to match the shoe's incline. czgtLDD.14_set_high_heels.1.var
Click and search for "14_set" or "czgtLDD" to locate the high heels. Select the item to apply it to your character. Clothing assets in VaM often require specific pose