Massive World and Village use databases to build everything and since 5.4 those databases can be shared.
Download and unzip the file in your project to the Massive folder directly like in the screenshot below, then add it to your database (for example for a biome, you add the database inside DT_AllBiome). Once this is done, the package will be usable through the drawing tool.
Example: Massive/StylizedFarmland/All the content. You need to add the zipped folder "StylizedFarmland" inside Massive.
Disclaimer: Those packages don't include the 3d meshes, you need to own both the tool (Massive World or Village) and the art from the asset store publishers and have both installed in your project.
