Product details in email template

Product details in email template

Hi, 

I am trying to generate email templates from either Invoices or Sales Orders that gives the customer the details of a purchase. Most fields seem to work quite ok, but nothing shows up when I try to get the order details into the template. Please see the template below. 

What am I doing wrong?

Regards, 
Benny


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Hi ${Contacts.First Name}

Please find your order details below. 

${SalesOrders.Product Details}


Total amount: ${SalesOrders.Grand Total}

Regards
Benny
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