$ sudo apt-get update
$ sudo apt-get install postbooks-schema-empty 

postbooks-schema-empty is installed in your system.

Make ensure the postbooks-schema-empty package were installed using the commands given below,

$ sudo dpkg-query -l | grep postbooks-schema-empty *

You will get with postbooks-schema-empty package name, version, architecture and description in a table

postbooks-schema-empty package basic information: