Restoring an older backup

Hi

I hope that someone can assist. I have recently been hit by ransomware and am slowly putting my system back together. One of the areas hit was my Calibre Library.

I am currently using version 4.12 and have found an old backup of my library on an external drive. It is a TIB File and has the file name of "Calibre Library_full_b136_s1_v1" (which was the standard backup from an earlier version of Calibre)

Can anyone tell me how I can restore this file (I cannot find any option in Calibre or on the web as to how I could do it).

I have created a new library called "Calibre Library" in my default directory, copied the file into that directory and then tried to do a restore but I keep getting the error that there is no backup file available.

Please can someone assist me.

Thank you

Gary