In addition to the Backup / Restore feature you may also create exact copies from existing sets of books, templates (installed in your TCASH4/Books directory or other sets of books in the TCASH4/Bin/Repository directory). The following options are available:

File → Backup / Restore.

File → Save as.

File → Create Set of Books (Copy from a Set of Books option on the Creation wizard).

Tools → Global processes  →  Copy from a Set of Books.