Fulltext search - ElasticSearch ingest (pdf,doc,...)

Please, give me an advice,
I need to search in full text in attachments (files) located in the directory ("… \ wwwroot \ scriptcase \ file \ doc ").
I installed ElasticSearch (v.6) and the ingest-attachment plugin.
As an external library, I added sc-elasticsearch from (“https://github.com/ricardobergamo/sc-elasticsearch”) to the scriptcase.
Can anyone advise me how to index this directory and search for text? The result will be a list of files in the grid.