Product Details Page:

Recently Viewed Products Architecture

On product.jsp (Product Default Template) page add the below code:

  <dsp:droplet name="/atg/commerce/catalog/ProductBrowsed">

<dsp:param name="eventobject" param="item" />

</dsp:droplet>

https://docs.oracle.com/cd/E24152_01/CRS.10-1/ATGCRSOverview/html/s0408recentlyviewedproductsarchitectu01.html