1)

Click the ellipsis 

2)

You can find the Extensions page by navigating to chrome://extensions/

Hover over "More Tools" and select "Extensions"

3)

Enable "Developer Mode" by switching its toggle towards right

4)

Click the "Load unpacked" button and select the extension directory

5)

Select the unzipped folder and click on Select button. 

6)

The extension has been successfully installed.
A generic toolbar icon will be created for the extension.
It could be a MyGuide icon or your company's logo