Cart recommendations
To show cart recommendations, add the following line of code somewhere on your shopping cart page. The template for this page is called cart.liquid. You can edit it using the Template Editor, as you did for the similar products panel.
It usually makes sense to place the code right at the end of the cart.liquid template file, but again some experimentation may be in order.
<div id="recommendify-cart" shop="{{ shop.domain }}" cart="{% for item in cart.items %}{{ item.product.id }},{% endfor %}"></div>
Here's what the cart recommendations look like on the demo store: