How to install a Gmail Add-on:
Sign-in to your Gmail account. Click the gear icon (Settings) in top right corner of the page.
Click See all settings.
Click on the Add-ons tab and click the Manage link under ‘Installed add-ons’. This will load the Gmail Add-ons library which can be browsed by popularity, ratings and categories.
Search for the add-on you want to install. Click Install and then the Continue button to confirm.
Follow the on-screen instructions to connect the add-on to your Gmail account and complete the installation.
Once it is installed, it will appear in Gmail’s add-on sidebar on the right side of the page.
How to remove a Gmail Add-on:
-Sign-in to your Gmail account. Click the gear icon (Settings) in top right corner of the page.
-Click See all settings.
-Click the Add-ons tab to view the tools you have installed.
-Click on the add-on you wish to remove.
-Click Uninstall and then the subsequent Uninstall App button to confirm its removal.