Pre-filling Pinterest descriptions for when someone pins from my website

Does anyone know how to pre-fill the descriptions for when someone pins a product or image using the Pinterest button from my website (www.keiditeng.com/shop)? I've been investigating for awhile and found this page: https://business.pinterest.com/en/blog/pin-it-button-technical-tune-up-5-tips-to-make-sharing-from-your-site-better, however I am not a coder and can't figure out where to inject the code for my individual products/images.

Thank you!

These two posts have been helpful for me: 

This one explains exactly what you're asking - https://www.untangledbiz.com/blog/2018/11/7/why-alt-text-not-the-right-place-for-pin-descriptions

This one explains how to make the most of rich pins if you don't feel like going through the trouble - https://thirtyeightvisuals.com/blog/pinterest-rich-pins-squarespace?fbclid=IwAR3MihzgrQd1XZXzwaOL5uoOftb4gzWsqe8oW-6CHzcgmhzVrk16fcKL9wA

However, with both of these methods I still have a few issues. Using the first link for guidance, I tried filling in "data-pin-description". When I post the pin, the description I had typed in shows up as the secondary small-text description down at the bottom of the pin info, by my profile image (if you just enable rich pins per the second link from thirtyeightvisuals above, that small-text description defaults to being your image alt text description, or the image filename if you didn't type in an image description). It still continues to pull my post description for the main description. I have no idea why it's doing this. How much more clear could the command "data-pin-description" be? Wordpress people say to include "alt="insert alt text here" as well, for the small-text description area. But that doesn't do anything for me. There's a new metadata tag called "data-pin-title" that's also supposed to enable you to choose a title other than your blog post title, but that doesn't work for me either.

If I just enable rich pins per the second link above, I have wayyy less problems. But every once in awhile, one of my pins won't follow the rules. Like, I've set the author to be "My Name | My Blogs Name". When I pin most pins, that is what the author field correctly states. But when I pin certain other ones, it just says "My Name" for the author. WHY. I'm with you, this is all confusing.