In your GUI, click on Help -> Help Topics, and search for
Restore "Internal Database" including the " marks
The entire procedure is there
It is important to know that by default the IDB cannot be restored to the same location. During the REstore, a file named 'idb.config' is altered to point at the Restore location (this is not documented). Once the Restore has been done correctly, the files and folders at teh original location can be deleted to save disk space