Urgent question - Facebook purchase event

[CapKirk]

Guys,

Please i need urgent help.

 I need to add the purchase event on my facebook pixel, is the only event that I need to track that doesn't come by  default with the integration of Shopify with the app "Facebook &Instagram".  

I saw this code on Facebook but i do not know where to install it and if these is the one.....

I tried creating manually a pixel by going to the shopify admin, "customer events", but im stucked here, i dont know how to continue.

// Step 1. Initialize the JavaScript pixel SDK (make sure to exclude HTML)

// Step 2. Subscribe to customer events with analytics.subscribe(), and add tracking
// analytics.subscribe("event_name", event => {
// pixel("track", "event_name", event.data);
// });

 

how should i proceed? 

I dont know how to code so any advice that can be given with the step by step very detailed of what to do will be super helpful.

Thank you so much