The "Base Code" for the Facebook Pixel can be placed in either:
a) the Settings section of your Nexternal Order Management System (OMS) Settings/ Edit Policies, Addenda, & Disclaimers / Tracking Code, or
b) the Layout section of the OMS (Layout / Advanced Layout / Head Addendum).
Code entered into either of these fields will be placed on every page in the store.
The "Standard Event Code" should be placed in Settings / Edit Policies, Addenda, & Disclaimers / Order Affiliate Addendum (same place any existing Facebook conversion code should be). Code entered here will fire when an order is submitted.
Note: The Order Affiliate Addendum tooltip question mark contains a list of variables that can be used to send specific order information to Facebook.