Creating A Shopify App With Delivery Method Pop-Up

[EriC142]

Hello everyone,

I'm looking to develop a Shopify app that will display an option-based pop-up every time users select a specific delivery method. I am still new in Shopify application development and would appreciate any assistance or suggestions from the community. Here is the URL of my store.

I would appreciate having someone provide me with the proper direction or recommend any information that might be helpful. I'm experienced with JavaScript; suggestions or best techniques for Shopify App development will be highly appreciated.

Thank you for your assistance.

Best Regards.