After enabling the Product Comparison add-on, the Compare option will appear when the store visitors hover over any product in the storefront. They can use this option to add products to the list.
It is also possible to add a product to the comparison list from the product details page.
Buyers can view products added to the list of comparisons on a special store page which they can reach from the store header:
Customers can use the "Differences only" check box option to choose whether they want to see only the parameters that differ between the selected products or all the parameters available for comparison.