Can I download a new furniture library for Sweet Home 3D? Where? How to import?
There are many ways to add furniture and other elements in Sweet Home 3D. The software offers the Import function through File > Import. There is a page created by the developers where you can see all the available resources.
Resources page: http://www.sweethome3d.com/importModels.jsp
Furniture Import Wizard: http://www.sweethome3d.com/userGuide.jsp#importing3DModels
Download new furniture models: http://www.sweethome3d.com/freeModels.jsp