DELIVERY LOOP TOP 3 ITEMS CATEGORY

Good morning,

I am starting to use this technology and I have found myself with a limitation, or surely I have no idea how to use this in an efficient way.

I am creating a workflow to get some customers who have bought some products of some categories, to whom I have to send an email with a top 3 products of the same category but not what they have already bought.

In short, I have the customers dissected and the products they should receive. Now my problem is how to send this information for each customer.
Do I have to make a loop? in that case how do I make a loop from a worflow?

I leave a screenshot for a better understanding.

Thank you,