How to add upsell product like the → https://www.flowersbox.co.uk/products/pink-clouds-hat-box
As i can see there is no form and on multi select the product gets add to cart
Thank you in Advance
This is a very complex request, you need to have experience with Liquid, CSS and JS.
If you have no experience, I recommend you to hire a professional.
Hope it helps!
I do have experience in coding, i needed some reference on link if possible @LitExtension