Recently Viewed Products

You could add the recently viewed widget to your sidebar https://docs.woothemes.com/document/woocommerce-widgets/

I would like to add it below my “related product” block here : https://tjc.apps-1and1.net/product/ring-example-1.

If the theme doesn’t have a widget area down there you won’t be able to without customisation.

Thanks. I will see that with the theme author.