You want to active a “crx” extension that is not from the Chrome Web Store and Chrome tells you that “Extensions, apps, and user scripts can only be added from the Chrome Web Store”.
The first thing to note is that CRX file is a ZIP file with a different extension. You can either open it with a zip program (like 7-zip) or rename it and change the CRX extension to ZIP and then use your operating system to get the files. Here are some basic steps:
- Unzip the contents of the CRX file to a directory anywhere (change the CRX extension to ZIP to make this easier if you like).
- Inside Chrome, go to settings then to extensions, then click “Load unpacked extension” and choose the directory you placed the unzipped files in.