How to create multiple checkbox add ons for product page upsell

I found this awesome (simple)tutorial for upselling on the product page.

However, the script only works for the upsell of 1 other item. I’ve tried playing around with the snippet and script to add another add on product but cant seem to figure it out.

How do I make this code work for multiple add on options? or does anyone have a link to a better tutorial for what I’m trying to achieve.


  

    
     
  

  
    

      

      

    

  

Hey, did you find an answer to this?