And why not SH3D 6.3???

Because he use repository version.

I didn't know how to use the Library Editor

You will learn; I will help You!

I didn't know how to limit the exported library file to just the things I created

You can't!
The furniture Library Editor is a separate tool.
While You are already able to make an archive with blocks, this is the next step. We are here to help You also.
BUT
1. Read this post . I've write it especially for guys like You.
2. Try to follow the instruction (not all at the start).
The purpose is to have a fully functional and updated SH3D.
Your Core2Duo is not a problem BUT if You have a dedicated graphic card You will need some more settings.
After this operation success we could go to next step.
(Only If You want [B-)] ).