Add Sitewide Code (Facebook Pixel, Google Tag Manager etc.)

To add sitewide (or global) code: Dashboard > Site Settings > Code Injection

Determine recommended code placement location (e.g. After <head> tag, Before </head> tag etc.)

Install Facebook Pixel - Part 1

The first step is to install the Facebook Standard Code. This code needs to be installed sitewide (or global). 

Install Facebook Pixel - Part 2

The 2nd step is to install the Facebook Event Code on the "Thank You" page using the Custom HTML element.

You will need to create a "Thank You" page if you do not have one.

If your goal is lead generation, select and install the "Lead" or "Complete Registration" event code.