Ecommerce Tracking using GTM

I am trying to set up ecommerce tracking using GTM.  I have injected the code in the header and footer (in the code injection area).  Do I need to add a dataLayer code as well in the confirmation page as well?  And will squarespace allow this code to fire on the confirmation page?  
 

I have read the best way to do it is input your Measurement ID key in the integration and squarespace should be passing the transaction info through to your Google Analytics property, but mine isn't showing any transaction in either UA or GA4 through this method.  

Hi @JasonGee1,

How is the setup going? Do you have a goal in mind of what you'd like to track? 

I'm working with an e-commerce brand to set up a Pinterest tracking pixel through GTM, and it sounds like we're working on similar things! I haven't seen any recommendations as far as putting GTM on the confirmation page. In regards to my application, I didn't find the datalayer codes helpful.