Check for high-resolution textures. Does the fabric look realistic (e.g., lace transparency, silk sheen)?
As a .var file, it should be a simple "plug and play" into your AddonPackages folder. Review whether the item shows up correctly in the "Clothing" menu under the expected tags. dlskd9.freebie_lingerie.1.var
If this file is from a specific creator's Patreon or a site like Hub (Virt-a-Mate Hub), I recommend checking the comment section on the original download page for specific user feedback regarding compatibility with the latest VaM versions. Check for high-resolution textures