Open VTube Studio
Click the Settings icon
Go to the Items or Accessories section
Click Open Item Folder or Open Asset Folder
Add your asset files to the correct folder
Use supported file formats such as PNG or PSD if required
Return to VTube Studio
Refresh or reload the item list
Select the asset from the list
Drag the asset onto your model or scene
Adjust position, size, and rotation as needed
Save the setup if you want to reuse it later