Make sure you have the latest version of Safari. To get the latest version of Safari, install the latest macOS. To keep Safari up to date from an earlier macOS, install the latest updates for that macOS.
Click here to locate the Whilo extension on the Apple Extensions Store and click "Install Now." Once the installation is complete you will see "Install Now" change to "Installed."
You should now see the Whilo icon to the left of your URL/Address bar in Safari, click the button and use your email and password to log in.
Now navigate to any product page you wish to add and hit this button.
The widget will do it's best to find the information it needs on the page, but you can complete the Title, Brand, Price, Category etc to correct it or fill in the blanks.
Next select wether you would like to add this to your Loves (your profile list) or a custom list you created in Whilo.