Checkout form modification

Site URL: https://www.infinix.com/checkout

Hello,

I'd like to add some additional wording on our Checkout form that says "Forget something? Continue shopping".  This would link to this page - https://www.infinix.com/all-products. 

I don't see any option currently to add a link or button. 

Thank you in advance. 
Stephanie

The checkout page cannot be modified it is a Squarespace security feature.

So the only two options are to use Express Checkout or adding items to a cart and then Check out?  Is that correct?

That is essentially correct.

Just a note. The checkout page is more amenable to customization.

Understood. Thank you for your quick response!