There's 2 different ways you can do it:

1.1 Blender

• Once the jewelry is bought and files have been downloaded. Open your avatar in Blender
• Import the jewelry FBX into Blender and place it where you want it
• Parent the jewelry to your avatar's armature
• Export avatar to Unity

1.2 Unity

• Once jewelry is bought and files have been downloaded. Open your avatar's Unity package
• Drag and drop the jewelry files into Unity
• Drag the jewelry FBX to your avatar's armature. **MAKE SURE THAT YOUR PUTTING IT ON THE RIGHT BONE YOU WANT IT TO BE
• Create/Add the materials to the jewelry

Read the Terms and Use for more information

You can commission Pupified for custom jewelry