In order to track conversions accurately (just for Confirmation page on the widget and not all of the pages) we need to use Google Tag Manager.
1. Create Google Tag Manager Account
Sign up using this link https://tagmanager.google.com
After the sign up you will receive your GTM code
Copy it and then go to your Diary in Settings > Restaurant Details > Other Details > Widget Tracking and paste the code right under your Google Analytics code.
2. Generate Facebook’s Conversion-tracking pixels code
Click Create Pixel
Select Checkout (or any other option if that is more relevant to your tracking) and fill in the name for the pixel.
Copy the pixel code into a notepad (you’ll need it in a second).
3. Adding the tracking to Google Tag Manager
In Google Tag Manager navigate to Container -> Tags -> Click New
Select Custom HTML Tag and paste the conversion code you just generated.
Click Some Pages
Fill in the fields like so:
Click Save Tag
Make sure you click Publish on the top right corner for the tag to work.