Facebook Tracking - Multiple Currencies - How to create variable in GTM

[helena-wong]

Hello,

We want to attribute conversion value when somebody adds a product to cart. These values are dynamic. Currency and price changes.

We have set up Facebook events through Google Tag Manager. How do we create a variable for the dynamic currency and price?

We have this template so far:

<script>

fbq('trackCustom', 'Button - add-to-cart',{

value: 

  currency: 

});

</script>

Do we need to create a data layer for value and currency?

And how do we do so?

Please help