The HttpWatch Chrome and Edge extensions are normally installed from the Google Web Store and the Microsoft Store by the HttpWatch installer. If you are installing on a PC with no internet access the extensions can be manually installed by following these steps:

1. Locate the CRX files for the HttpWatch extensions. HttpWatchForChrome.crx and HttpWatchForEdge.crx are installed with HttpWatch - by default they will be in the folder C:\Program Files (x86)\HttpWatch
2. In Chrome open the extensions page
3. Turn on Developer Mode using the switch on the extensions page
4. Drag the HttpWatchForChrome.crx file from step 1) onto the extensions page and confirm that you want to add the HttpWatch Extension
5. Turn off Developer Mode
6. Repeat with Edge but use the HttpWatchForEdge.crx file

More information is available in this blog post:

https://blog.httpwatch.com/2017/11/15/installing-a-chrome-extension-without-an-internet-connection/