Just download the repository and extract everything in your InDesign scripts folder. On Window systems the path is something like: ~\AppData\Roaming\Adobe\InDesign\Version 16.0\de_DE\Scripts\Scripts ...

This repository contains word-files-to-indesign.jsx, an Adobe InDesign script that places multiple DOCX files into a document using predefined master pages. It automates creating spreads for each DOCX ...