Where do I paste the code for a popup on my shop page?

New Member
1 0 0

I have a custom created code for a pop up box written by a techy friend that I would like to appear on the shop page of my store.  I am using a collection with "all products" as my main shop page. Can anyone show me the correct location in the liquid code to paste the code for the pop up?  I am using the canopy theme if that helps.  Here is my shop page: https://glory-garden.myshopify.com/collections/all  Thank you!