If your Zagomail account is connected with one the integrations: Shopify, Bigcommerce, Woocommerce,...then I will show you how easy to add a product to your template.
You need to follow the simple steps below:
After creating a campaign and after the first steps click on "Drag and drop editor"
Drag and drop the block "product" in the position you want
Click on the block then select the integration you have (E.g. Shopify)
Select a product
Choose a product then save