Changing files to links in inventory section on product pages

Site URL: https://www.wearenym.com/store-1/p/nym-issue-1

I'm trying to create product pages where I can provide a link to products rather than a file. Is it possible to change this in the inventory section of the product pages? 

Thanks @paul2009 Are you able to help with any of the below too please? 
 

1. In the shop, once you've clicked on something to add to cart there's no return to shop button so you have to navigate back via main menu - Can i add something in here?

2. See screen grabs below of the messages after during/checkout, not sure if the sizing of copy or the actual text can change... this is viewing on mobile.

4 minutes ago, emma-gardner said:

Are you able to help with any of the below too please?

To keep the thread on-topic I recommend you add new questions for these additional questions. 🙂

I don't understand the context of Q1 so you may need to explain this a little more. For example, what's the URL of the page where this happens?

Regarding Q2, there's a similar thread here: