Installing Extensions - tfmorris/OpenRefine GitHub Wiki
How to install extensions.
This is applicable to version 2.0 and later only.
Step 1. In OpenRefine's front page (http://127.0.0.1:3333/), click Browse workspace directory at the bottom of the project list. This should open up the workspace directory in your system's file browser.
Step 2. In the workspace directory, create a sub-directory called "extensions" if there isn't one already.
Step 3. Shut down OpenRefine.
Step 4. Download the extension .zip file and unzip it to a sub-directory under the "extensions" directory that you have just created.
Step 5. Start OpenRefine up again.