The pixel is added in OneTrack already. You need to check in Snapchat pixel helper, if you see the pixel can track Page view, View content, Add to cart, Start checkout and Purchase event, so the pixel is working well
Page View: A pixel can track when a user loads a specific page on a website.
View Content: When a user views a specific product or piece of content, a pixel can be triggered to record this event.
Add Cart: When a user adds an item to their shopping cart or basket, a pixel can be triggered to track this action.
Start Checkout: This event is tracked when a user proceeds to the checkout process to complete a purchase. It indicates that the user is in the final stages of making a transaction.
Purchase Event: When a user successfully completes a purchase, a pixel associated with the tracking system is triggered in thank_you page.
Check the data in your Snapchat Event Manager
You can see the overview of data here
And detailed here:
If you are still struggling with Snapchat Pixels, please feel free to contact live chat support or onetrack.commerce@gmail.com for the best assistance.