Cannot find the Order Entry folder in $ORACLE_HOME/demo/schema/
That is 12.1 documentation. You have a 12.2 database.

Installing Sample Schemas


  Starting with Oracle Database 12c Release 2, the latest version of the
  sample schema scripts are available on GitHub at
  https://github.com/oracle/db-sample-schemas/releases/latest.
  
  During a complete installation of Oracle Database, the HR schema can
  be installed either manually or automatically when creating a database
  using the dbca option. All the other sample schemas must be installed
  manually via the scripts available on GitHub.


You can download the scripts from the above github URL.